Operation Battle of Tarawa

The 'Battle of Tarawa' was fought between US and Japanese forces for the atoll of Tarawa in the Gilbert islands group as part of the 'Galvanic' operation by the US forces to take the Gilbert islands group (20.23 November 1943).

Almost 6,400 Japanese, Koreans and Americans died in the fighting, mostly on and around the small island of Betio, at the extreme south-west of Tarawa atoll, in the 'Longsuit' undertaking.

The 'Battle of Tarawa' was the first US offensive in the critical central region of the Pacific Ocean. It was also the first time in the Pacific War that the USA had faced serious Japanese opposition to an amphibious landing. Earlier US landings had met little or no initial resistance, but on Tarawa the 4,500 Japanese defenders were well-supplied and well-prepared, and then fought almost to the last man, exacting a heavy toll on the US Marine Corps in fighting that lasted 76 hours.

In order to establish forward air bases capable of supporting operations across the central part of the Pacific Ocean, to the Philippine islands group and finally to the Japanese home islands, the USA planned to take the Mariana islands group, which were known to be very strongly defended. US naval doctrine of the time held that in order for attacks to succeed, land-based aircraft would be required to weaken the defences and protect the invasion forces. The nearest islands capable of supporting such an effort were those of the Marshall islands group. Taking the Marshall islands group would provide the base needed to launch an offensive on the Mariana islands Group, but the former was cut off from direct assault from the Hawaiian islands group by the Japanese garrison and air base on the small island of Betio, on the western side of the atoll of Tarawa in the Gilbert islands group to the south-east of the Marshall islands group. Thus, the launching of the offensive to take the Mariana islands group had therefore to start far to the east with the seizure of Tarawa.

Following the completion of the Guadalcanal campaign, Major General Julian C.Smith’s 2nd Marine Division had been withdrawn to New Zealand for rest and rehabilitation. Losses were replaced, and the men were given a chance to recover from the malaria and other illnesses that had weakened them through the fighting in the Solomon islands group. On 20 July 1943, the Joint Chiefs-of-Staff directed Admiral Chester W. Nimitz, the commander-in-chief of the US Pacific Fleet and the Pacific Ocean Areas command, to prepare plans for an offensive operation in the Gilbert islands group. In August, Admiral Raymond A. Spruance was flown to New Zealand to meet with Smith, the new commander of the 2nd Marine Division, and initiate the planning of the invasion with the division’s staff.

Located about 2,400 miles (3865 km) to the south-west of Pearl Harbor, Betio is the largest island of the Tarawa atoll. The small, flat island lies at the southernmost reach of the lagoon, and was the base of the majority of the Japanese troops. Shaped roughly like a long, thin triangle, the tiny island is approximately 2 miles (3.2 km) long. It is narrow, being only 800 yards (730 m) across at its widest point. A long pier had been built jutting out from the northern shore, onto which cargo ships could unload while anchored beyond the 550-yard (500-m) wide shallow reef which surrounds the island. The island’s northern coast faces into the lagoon, while the southern and western sides face the deep waters of the open ocean.

Following Colonel Evans F. Carlson’s diversionary raid on Makin island in August 1942, the Japanese command had become aware of the strategic significance but vulnerability of the Gilbert islands group. Thus the 6th Yokosuka Special Naval Landing Force reinforced the island in February 1943. In command was Rear Admiral Tomonari Saichiro, an experienced engineer who directed the construction of the sophisticated defensive structures on Betio. On arrival, the 6th Yokosuka Special Naval Landing Force became the garrison with the revised identification 3rd Special Base Defence Force. Tomonari’s primary goal in the Japanese defensive scheme was to halt the attackers in the water or pin them on the beaches. A very large number of pillboxes and firing pits was constructed, these offering excellent fields of fire over the water and sandy shore. In the interior of the island was the command post and a number of large shelters designed to protect defenders from air attack and naval gunfire bombardment. The island’s defences were not set up for a battle in depth across the interior. The interior structures were large and ventilated, but had no firing ports, so the defenders were limited to firing from the doorways.

The Japanese worked intensively for nearly a year to fortify the island. To aid the garrison in this task, the 1,247 men of the 111th Pioneers, similar to the 'Seabee' construction troops of the US Navy, along with the 970 men of the 4th Fleet's construction battalion, were delivered to the island. About 1,200 of the men in these two units were Korean labourers. The garrison itself comprised men of the Imperial Japanese navy: the special naval landing forces were the troop units of the Imperial Japanese navy, and were known by US intelligence to be more highly trained, better disciplined, more tenacious and to have better small unit leadership than comparable units of the Imperial Japanese army. The 3rd Special Base Defence Force assigned to Tarawa had a strength of 1,112 men, who were reinforced by the 7th Sasebo Special Naval Landing Force's 1,497 men. The defence force was led by Commander Takeo Sugai, and was bolstered by 14 Type 95 light tanks under the command of Ensign Ohtani.

Some 14 coast-defence guns, including four Vickers 8-in (203-mm) weapons bought during the Russo-Japanese War from the British, were secured in concrete bunkers around the island to guard its open-water approaches. It was thought these large-calibre guns would make it very difficult for a landing force to enter the lagoon and attack the island from the northern side. The island had a total of 500 pillboxes or 'stockades' built of palm logs and sand, many of which were reinforced with cement. Some 40 pieces of artillery were scattered around the island in various reinforced firing pits. An airfield was cut into the island’s underbush straight down the island’s centre. Trenches connected all parts of the island, allowing troops to move under cover when necessary to wherever they were needed. As the command believed their coast-defence guns would protect the approaches into the lagoon, it was anticipated that any attack on the island would come from the open waters of the western or southern beaches. Rear Admiral Keiji Shibazaki, a commander experienced in combat from the campaigns in China, relieved Tomonari on 20 July 1943, in anticipation of the coming fight. Shibazaki continued the defensive preparations right up to the day of the US landings. He encouraged his troops with the wods that 'it would take one million men one hundred years' to take Tarawa.

In the Pacific theatre, the chain of command for the US assault on Tarawa extended from Nimitz in the Hawaiian island group to Admiral Raymond A. Spruance flying his flag as commander of the 5th Fleet in the heavy cruiser Indianapolis, Vice Admiral Richmond K. Turner flying his flag as the commander of the V Amphibious Force in the battleship Pennsylvania and leading the Makin assault by the Northern Attack Force (Task Force 52) with Major General Ralph C. Smith;sa 27th Division and Vice Admiral Harry W. Hill flying his flag in the battleship Maryland and leading the Tarawa assault by the Southern Attack Force (Task Force 53) with Major General Julian C. Smith’s 2nd Marine Division. Under the command of Major General Holland M. Smith, the V Amphibious Corps supervised two attack forces, in which the 2nd Marine Division comprised Colonel David M. Shoup’s 2nd Marine Regiment, Colonel Maurice G. Holmes’s 6th Marine Regiment, Colonel Elmer E. Hall’s 8th Marine Regiment, Colonel Thomas E. Bourke’s 10th Marine Regiment (Artillery) and Colonel Cyril W. Martyr’s 18th Marine Regiment (Engineer).

As noted above, the defence of Tarawa was vested in Shibazaki’s Gilbert Islands Defence Forces with the 3rd Special Base Force, the 7th Sasebo Special Naval Landing Force, the 111th Construction Unit, and a detachment of the 4th Fleet Construction Department.

The US invasion force for the Gilbert islands group was the largest yet assembled for a single operation in the Pacific theatre, and comprised 17 aircraft carriers (six fleet carriers, five light fleet carriers, and six escort carriers), 12 battleships, eight heavy cruisers, four light cruisers, 66 destroyers and 36 transport ships. On board the transports were the 2nd Marine Division bound for Tarawa and the 27th Division bound for Makin, with a total of about 35,000 troops.

As the invasion fleet reached Tarawa in the pre-dawn hours, the island’s four 8-in (203-mm) guns opened fire, and a gunnery duel soon developed as the 16-in (406-mm) main batteries on the battleships Colorado and Maryland began counter-battery fire. The warships' fire was accurate, and several 16-in (406-mm) shells found their marks. One shell penetrated the ammunition storage for one of the Japanese guns, triggering a huge explosion as the ordnance went up in a massive fireball. Three of the four guns were knocked out in short order. One continued its intermittent, though inaccurate, fire through to the battle’s second day. The damage to the big guns left the approach to the lagoon open.

Following the gunnery duel and an air attack of the island at 06.10, the naval bombardment of the island began in earnest and was sustained for the next three hours. Two minesweepers, with two destroyers to provide covering fire, entered the lagoon before dawn and cleared the shallows of mines. A light from one of the minesweepers then guided the landing craft into the lagoon, where they awaited the end of the bombardment. The plan was to land marines on the north beaches, divided into three sections: Beach Red 1 in the far west of the island, Beach Red 2 in the centre just to the west of the pier, and Beach Red 3 to the east of the pier. Beach Green was a contingency landing area on the western shoreline and was used for landings on the second day, and Beaches Black 1 and 2 made up the southern shore of the island and were not used. The airstrip, extending approximately east/west, divided the island into northern and southern sectors.

US Marine Corps planners had expected the normal rising tide to provide a water depth of 5 ft (1.5 m) over the reef, allowing their Higgins boats, hich had a draught of 4 ft (1.2 m), room to spare. On the first and second days of the landing, however, the sea experienced a neap tide, and did not rise. In the words of some observers, 'the ocean just sat there', leaving a mean depth of only 3 ft (0/9 m) over the reef. A New Zealand liaison officer, Major Frank Holland, had 15 years experience of Tarawa and warned that there would be at most a 3-ft (0.9-m) depth as a result of the tides. Shoup warned his troops that there would be a 50/50 chance that they would need to wade ashore, but the attack was not delayed until the arrival of more favourable spring tides.

As the supporting naval bombardment lifted, the marines started their attack from the lagoon at 09.00, some 30 minutes later than planned, and discovered that the tide had not risen sufficiently to allow their shallow-draught Higgins boats to clear the reef. Only the tracked LVT 'Alligator' vehicles were able to get across. With the pause in the naval bombardment, those Japanese who had survived the shelling were again able to man their firing pits, and men from the southern beaches were shifted to the northern beaches. As the LVTs made their way over the reef and into the shallows, the number of Japanese troops in the firing pits slowly began to increase, and the volume of fire the LVTs faced gradually intensified. The LVTs had holes punched through their unarmoured hulls, and many were knocked out of the battle. The 'Alligators' which did make it to the beach then could not clear the sea wall, leaving the men in the first assault waves pinned down against the log wall along the beach. A number of 'Alligators' went back out to the reef in an attempt to carry in the men stuck there, but most of these LVTs were too badly holed to remain seaworthy, leaving the marines stranded on the reef some 500 yards (460 m) off shore. Half of the LVTs had been knocked out of action by the end of the first day.

Shoup was the senior officer of the landed forces, and took command of all landed marines upon his arrival on shore. Although wounded by an exploding shell soon after landing, Shoup had the pier cleared of Japanese snipers and rallied the first wave of marines, who had become pinned down behind the limited protection of the sea wall. Over the next two days, working without rest and under constant Japanese fire, Shoup directed attacks against strongly defended Japanese positions, pushing forward despite daunting defensive obstructions and heavy fire. Throughout, Shoup was repeatedly exposed to Japanese small arms and artillery fire, inspiring the forces under his command.

Early attempts to land tanks for close support and to get past the sea wall failed when the LCM landing craft carrying them hung up behind the reef. Some of these craft were hit out in the lagoon as they waited to move in to the beach, and either sank outright or had to withdraw while taking on water. Two M3 Stuart light tanks were landed on the eastern end of the beach but were soon knocked out of action. The commander of 3/2nd Marines found several LCMs near the reef and ordered them to land their M4 Sherman medium tanks and head to Beach Red 2. The LCMs dropped ramps and the six tanks came down, climbed over the reef and dropped into the surf beyond. They were guided to the shore by marines on foot, but several of these tanks fell into holes caused by the naval gunfire bombardment and sank. The surviving Sherman tanks on the western end of the island proved considerably more effective than the lighter Stuart tanks, and helped to push the US line to about 300 yards (275 m) from the shore. One tank became stuck in a trap and another was knocked out by a magnetic mine. The remaining tank took a shell hit to its barrel and had its 75-mm (2.95-in) gun disabled, and was thus used as a mobile machine gun pillbox for the rest of the day. A third platoon was able to land all four of its tanks on Beach Red 3 at about 12.00 and operated them successfully for much of the day, but by the fall of night only one tank was still in action.

By 12.00 the marines had taken the beach inland as far as the first line of Japanese defences. By 15.30 the line had moved inland in places but was still generally stuck along the first line of defences. The arrival of the tanks started the line moving on Beach Red 3 and the end of Beach Red 2 (the right flank, as viewed from the north), and by the fall of night the US line was about half-way across the island and only a short distance from the main runway.

In addition, Major Michael P. Ryan, a company commander, had gathered remnants of his company with diverse marine stragglers and sailors from other landing waves, as well as two Sherman tanks, and had diverted them onto a more lightly defended section of Beach Green. This extemporised unit came to be known later as 'Ryan’s Orphans'. Ryan, who had been thought to be dead, arranged for naval gunfire and mounted an attack that cleared the island’s western end.

The communication lines which the Japanese had installed on the island had been laid at only a shallow depth and had been destroyed in the naval bombardment, effectively preventing Shibazaki from exercising direct control of his troops. In the middle of the afternoon, he and his staff abandoned the command post at the northeast end of the airfield, to allow it to be used to shelter and care for the wounded, and prepared to move to the south side of the island. He had ordered two of his Type 95 light tanks to act as a protective cover for the move, but a 5-inch naval artillery shell exploded in the midst of his headquarters personnel as they were assembled outside the central concrete command post, resulting in the death of the commander and most of his staff. This loss further complicated Japanese command problems.[21][22]

As night fell on this first day of 'Longsuit', the Japanese maintained a sporadic harassing fire, but did not launch a counterattack on the marines clinging to their beach-head and the territory won in the day’s hard fighting. Shibazaki had been killed and the communication lines destroyed, each Japanese unit had been acting in isolation since the start of the naval bombardment. The marines brought ashore a battery of 75-mm (2.95-in) pack howitzers and readied them for action on the following day, but most of the second wave of men was unable to land, and these marines spent the night floating in the lagoon without food or water, trying to sleep in their Higgins boats. During the night, a number of Japanese swam to some of the wrecked LVTs in the lagoon, and to the Saida Maru, a wrecked Japanese steamship lying to the west of the main pier. They waited for dawn, when they intended to fire on the marines from the rear. Lacking central direction, however, the Japanese were unable to co-ordinate any counterattack against the toehold the marines held on the island. The feared counterattack never came, and the marines held their ground. By the end of the first day, of the 5,000 marines put ashore, 1,500 had become casualties, either dead or wounded.

On 21 November, the marines holding a thin line on the island were ordered to attack Beaches Red 2 and 3, and to push inward and divide the Japanese defenders into two sections, expanding the bulge near the airfield until it reached the southern shore. The forces on Beach Red 1 were directed to secure Beach Green, extending right across the island’s western end, for the landing of reinforcements in the form of two battalions of the 6th Marines. The effort to take Beach Green Beach initially met heavy resistance. Naval gunfire was used to reduce the pillboxes and gun emplacements barring the way. Inching their way forward, artillery spotters were able to direct the naval gunfire directly onto the machine gun posts and remaining strongpoints. With the major obstacles reduced, the marines were able to take the positions in about one hour of combat with relatively few losses.

Operations along Beaches Red 2 and 3 were considerably more difficult. During the night the defenders had set up several new machine gun positions between the closest approach of the forces from the two beaches, and fire from those machine gun positions cut off the US forces from each other for some time. By 12.00, the US forces had brought up their own heavy machine guns, and the Japanese posts were then put out of action. By the early afternoon the US forces had crossed the runway and occupied abandoned defensive works on its southern side.

At about 12.30 a message arrived that some of the defenders were making their way across the sandbars from the extreme eastern end of the islet to Bairiki, the neighbouring islet to the south-east. Portions of the 6th Marines were then ordered to land on Bairiki to seal off this retreat path. The marines formed with armour and pack artillery, and were able to start their landings at 16.55. They took machine gun fire, so aircraft were despatched to locate and suppress the guns. The marines landed without meeting further fire, and it was later found that only a single pillbox with 12 machine guns had been set up by the forces assumed to be escaping. They had a small tank of petrol in their pillbox, and when it was hit with fire from the aircraft the entire force was burned. Later, other units of the 6th Marines were landed unopposed on the northern end of Beach Green near Beach Red 1.

By the end of the second day, the entire western end of Betio was in US hands, and the marines had established a fairly continuous line between Beaches Red 2 and 3 around the airfield aprons. A separate group had moved across the airfield and established a perimeter on the southern side, up against Beach Black 2. The groups were not in contact with each other, with a gap of more than 500 yards (460 m) between the forces at Beaches Red 1/Green and Beach Red 2, and the lines on the northern side inland from Red 2/Red 3 were not continuous.

The third day of battle, 22 November, took the form primarily of consolidating the existing lines along Beaches Red 1 and 2, an eastward thrust from the pier, and moving additional heavy equipment and tanks ashore onto Beach Green at 08.00. During the morning the forces originally landed on Beach Red 1 made some progress toward Beach Red 2 but took casualties. Meanwhile, the 6th Marines, who had landed on Beach Green to the south of Beach Red 1, formed up while the remaining battalion of the 6th Marines landed.

By the afternoon the 1/6th Marines was sufficiently organised and equipped to take to the offensive and, at 12.30, pressed the Japanese forces across the southern coast of the island. By late afternoon the battalion had reached the eastern end of the airfield and had formed a continuous line with the forces that had landed on Beach Red 3 two days earlier. By the evening the remaining Japanese forces had been either pushed back into the tiny area of land to the east of the airstrip, or were operating in several isolated pockets near Beaches Red 1 and 2 and near the western edge of the airstrip.

That night the Japanese forces formed for a counterattack, which started at about 19.30. Small units were sent in to infiltrate the US lines in preparation for a full-scale assault. The assembling forces were broken up by concentrated artillery fire, and the assault never took place. Another attempt, a large banzai attack, was made at 03.00 and met with some success, killing 45 marines and wounding 128. With support from the 5-in (127-mm) guns of the destroyers Schroeder and Sigsbee, the marines killed 325 of the attackers.

At 04.00 on 23 November, the Japanese attacked Major Jones’s 1/6th Marines in force. About 300 Japanese launched a banzai charge into the lines of Companies A and B. Receiving support from the 1/10th Marines' 75-mm (2.95-inm) pack howitzers and the guns of the destroyers Schroeder and Sigsbee, the marines were able to beat back the attack but only after calling artillery to within 80 yards (75 m) of their own lines. When the assault ended about an hour later, there were 200 Japanese dead in the marines' front lines and another 125 beyond their lines. At 07.00 US Navy fighter-bombers and dive-bombers started to soften the Japanese positions on the eastern tip of the island. After 30 minutes of air attack, the pack howitzers of 1/10th Marines opened on the Japanese positions, and 15 minutes later the US Navy began the last part of the bombardment with a further 15 minutes of shelling. At 08.00, the 3/6th Marines under the command of Lieutenant Colonel McLeod attacked, Jones’s 1/6th Marines having been pulled off the line after suffering 45 killed and 128 wounded in the previous night’s fighting. As a result of the island’s narrowing terrain, Companies I and L of the 3/6th Marine formed the entire marine front with Company K in reserve. The marines advanced quickly against the few Japanese left alive on the eastern tip of Betio. The marines were accompanied by two Sherman tanks, with five light tanks in support and engineers in direct support.

Companies I and L advanced 350 yards (320 m) before meeting anything in the way of serious resistance, namely interconnected bunkers on Company I’s front. McLeod ordered Company L to continue its advance, thereby bypassing the Japanese position. At this point Company L made up the entire front across the 200-yard (185-m) front across the entire width of Betio’s eastern end, while Company I reduced the Japanese strongpoint with the support of one of the medium tanks and attached demolition/flamethrower teams provided by the engineers. As the marines of Company I closed in, the Japanese broke from cover and attempted to retreat down a narrow defile. Alerted to the attempted retreat, the tank commander fired in enfilade at the line of fleeing soldiers. The near total destruction of the Japanese soldiers' bodies made it impossible to know how many men were killed by this single shot but it was estimated that 50 to 75 men perished. While the 3/6th Marines' Company L advanced down the eastern end of the island, Major Schoettel’s 3/2nd Marines and Major Hay’s 1/8th Marines were clearing the Japanese pocket that still existed between Beaches Red 1 and 2. This pocket had been resisting the advance of the marines' landing on Beaches Red 1 and 2 since the first day, and the marines had not yet been able to move against it.

The 1/8th Marines advanced on the pocket from the east (Beach Red 2) while the 3/2nd Mariones advanced from the west (Beach Red 1). Major Hewitt Adams led an infantry platoon supported by two pack howitzers from the lagoon into the Japanese positions to complete the encirclement, and by 12.00 the pocket had been destroyed. On the eastern end of the island, Company L of the 3/6th Marines continued to advance, bypassing pockets of resistance and leaving them to be cleared by tanks, engineers and air support. By 13.00 the marines had reached the eastern tip of Betio. The 3/6th Marines had killed some 475 Japanese during the morning of 23 November, losing only nine men killed and 25 wounded. Back at the Beaches Red 1/Red 2 pocket there was no accurate count of the Japanese dead. There were an estimated 1,000 Japanese alive and fighting on the night of 22 November, 500 on the morning of 23 November and only between 50 and 100 when the island was declared secure at 13.30 on 23 November.

For the next several days the 2/6th Marines moved up through the atolls remaining islands and cleared them of Japanese, completing this effort on 28 November. The 2nd Marine Division started shipping out soon after this, and had been completely withdrawn by a time early in 1944.

Of the 3,636 Japanese of the garrison, only one officer and 16 enlisted men surrendered. Of the 1,200 Korean labourers brought to Tarawa to construct the defenses, only 129 survived. All told, 4,690 of the island’s defenders were killed. The 2nd Marine Division suffered 894 men killed in action (48 officers and 846 enlisted men), while an additional 84 of the wounded survivors later succumbed to their wounds. Of these, eight were officers and 76 enlisted men. A further 2,188 men (102 officers and 2,086 enlisted men) were wounded in the battle. Of the approximately 12,000 men of the 2nd Marine Division committed on Tarawa, 3,166 officers and men thus became casualties. Nearly all of these casualties were suffered in the 76 hours between the landing at 09.10 on 20 November and the time at which the island of Betio being declared secure at 13.30 on 23 November.

The heavy US casualties suffered on Tarawa sparked public protest, for headline reports of the high losses could not be understood for such a small and seemingly unimportant island. The public reaction was aggravated by the unguardedly frank comments of some of the US Marine Corps' senior commanders. Major General Holland M. Smith, commander of the V Amphibious Corps and who had toured the beaches after the battle, likened the losses to Pickett’s Charge at Gettysburg. Nimitz himself was inundated with angry letters from the families of men killed on the island.

Back in Washington, DC, the newly appointed commandant of the US Marine Corps, Lieutenant General Alexander A. Vandegrift, the widely respected and highly decorated veteran of Guadalcanal, reassured the Congress, pointing out that 'Tarawa was an assault from beginning to end'. An editorial in The New York Times on 27 December 1943 praised the marines for overcoming Tarawa’s rugged defences and fanatical garrison, and warned that future assaults in the Marshall islands group might well result in still heavier losses: 'We must steel ourselves now to pay that price.'

Nimitz launched the 'Cataract' operation to take the Marshall islands group, to the north-west of the Gilbert islands group, 10 weeks after the seizure of Tarawa. Aircraft flown from airfields at Betio and Abemama proved highly valuable.

Following the 'Battle of Tarawa', the 2nd Marine Division was shipped to Hawaii, leaving the 2/6th Marines behind to clear the battlefield of ordnance, provide security for the 'Seabees' rebuilding the airstrip into Hawkins Field and aid in the burials. The 2nd Marine Division remained in Hawaii for six months, refitting and training, until committed in its next major amphibious landing, the 'Battle of Saipan' in the Forager' campaign for the Mariana islands group in June 1944.

The greater significance of the 'Battle of Tarawa' to the US success in the Marshall islands group proved to be the lessons learned from the battle. It was the first time in the war that a US amphibious landing had been opposed by well entrenched, determined defenders. Previous landings, such as the 'Watchtower' landing on Guadalcanal, had been unexpected and met with little or no initial resistance. At the time, Tarawa was the most heavily defended atoll invaded by Allied forces in the Pacific theatre. The US losses at Tarawa resulted from several factors, among which were the miscalculation of the tide and height of the obstructing coral reefs, the operational shortcomings of the landing craft then available, the inability of the naval bombardment to effect a decisive degradation of the defences of a well entrenched opponent, and the difficulties of co-ordinating and communicating between the different military branches involved. US Navy battleships and cruisers had fired some 3,000 shells onto Tarawa in the three hours before the landings, and 'This was by far the heaviest bombardment of an invasion beach ever delivered up to that time. Yet it proved inadequate…The high explosive shells employed by the bombarding ships usually went off before penetrating the Japanese defensive works [thus] doing little real damage.' For the subsequent campaign in the Marshall islands group, the naval bombardments lasted one month and included the use of armour-piercing shells, while the landing craft also had armour protection.

The failures of the Tarawa landing were a major factor in the establishment of underwater demolition teams. After the 'Battle of Tarawa', the 'need for the UDT in the South Pacific became glaringly clear'. The 'landing on Tarawa Atoll emphasized the need for hydrographic reconnaissance and underwater demolition of obstacles prior to any amphibious landing.' After the Tarawa landing, Turner directed the formation of nine underwater demolition teams, and 30 officers and 150 enlisted men were moved to the Waimānalo Amphibious Training Base to form the nucleus of a demolition training programme. This group became Underwater Demolition Teams 1 and 2.