The 'Battle of the Badung Strait' was a naval engagement of the Pacific campaign between ships of the American-British-Dutch-Australian Command and the Imperial Japanese navy in the waters of the Indonesian archipelago (19/20 February 1942).

In the engagement, a force of just four Japanese destroyers defeated an Allied force that both outnumbered and outgunned it, sinking the Dutch destroyer Piet Hein and escorting two transport vessels to safety. The battle demonstrated the Imperial Japanese navy’s overall superiority over the Allies in night fighting.

One battalion of Lieutenant General Yuichi Tsuchihashi’s 48^th Division landed on the island of Bali on 18 February 1942, one of the objectives of the 'S' (i) operation, at a time when the Dutch Schout-bij-Nacht Karel Doorman’s Allied naval forces were scattered around the Indonesian archipelago, but the invasion of Bali could not be ignored as its seizure would provide the Japanese with an air base within range of the ABDA naval base at Soerabaja, so Doorman ordered all available warships to the area. The short notice gave no time for any concentration of the ships, so several Allied forces were to attack the Japanese in the Badung Strait on the south-eastern side of Bali in Indonesia. The strait lies between the islands of Bali and Nusa Penida, and measures about 37 miles (60 km) in length and 12.5 miles (20 km) in width.

The first Allied vessels to engage were a pair of submarines, the US Seawolf and the British Truant, both of which attacked the Japanese convoy on 18 February. The submarines inflicted no damage and were driven off by depth charges from Japanese destroyers. Laton the same day, 20 US aircraft attacked the convoy, but succeeded only in damaging the transport Sagami Maru.

Realising that the invasion convoy was likely to be attacked once again, the Japanese fell back to the north as soon as possible. The light cruiser Nagara and the destroyers Wakaba, Hatsushimo and Nenohi were well away and took no part in the action. The last ships to leave were the transports, each escorted by two destroyers. The 7,180-ton Sasago Maru was escorted by Asashio and Oshio, and the heavily damaged 7,189-ton Sagami Maru was escorted by Michishio and Arashio.

The first Allied group, comprising the Dutch light cruisers De Ruyter and Java, the Dutch destroyer Piet Hein and US John D. Ford and Pope, sighted the Japanese in the Badung Strait at about 22.00 on 19 February and opened fire 25 minutes later. No damage was done in this exchange of fire, and the two Dutch cruisers continued through the strait to the north-east to give the destroyers a free hand to engage with torpedoes. Then Piet Hein, Pope and John D. Ford came into range, and at 22.40, a 'Long Lance' torpedo from Asashio hit Piet Hein, the detonation of the large warhead sinking the Dutch destroyer immediately. Asashio and Oshio then exchanged gunfire with [e[Pope and John D. Ford, forcing the two US destroyers to retire to the south-east instead of following the cruisers to the north-east.

In the darkness, Asashio and Oshio mistook each other for Allied ships and fired on each other for several minutes, without any damage.

About three hours later, the second group of ABDA ships, comprising the light cruiser Tromp and the US destroyers John D. Edwards, Parrott, Pillsbury and Stewart, reached the Badung Strait. At 01.36, Stewart, Pillsbury and Parrott launched torpedoes but enjoyed no success. Then Oshio and Asashio sortied again and there followed another exchange of gunfire. Tromp was hit by 11 5-in (127-mm) shells from Asashio, severely damaging her, and but she too fired and hit both Japanese destroyers, killing four men on Asashio and seven on Oshio. Tromp later had to return to Australia for repairs.

Arashio and Michishio had been ordered by Rear Admiral Kyuji Kubo to turn back, and at about 02.20 they joined the battle. Michishio was hit by shells from Pillsbury, John D. Edwards and Tromp, which killed 13 of her crew and wounded another 83. The Japanese destroyer lost speed and had to be taken in tow after the battle. During these exchanges, Stewart also suffered damage to her superstructure, and one the impact of one shell opened seams below the waterline aft and flooded the steering engine room. Both groups of ships turned away, and the engagement was over.

The third ABDA group of seven torpedo boats arrived in the Badung Strait at about 06.00 but did not encounter any Japanese ships. The battle was a significant victory for the Japanese, who had driven off a much larger Allied force, sunk the destroyer Piet Hein, damaged the destroyer Stewart and severely damaged the cruiser Tromp. Meanwhile, the Japanese had sustained little damage themselves, and had protected their transport ships.

Bali’s garrison of 600 Dutch-officered local militia offered no resistance to the Japanese, who captured its airfield intact. The Japanese continued their conquest of the Dutch East Indies with the capture of Timor on 20/23 February. The ABDA forces engaged in the Badung Strait were decisively defeated in the Battle of the Java Sea on 27 February 1942, in which the Dutch cruisers Java and De Ruyter were sunk and Doorman was killed. Tromp evaded this fate, for she had been withdrawn to Australia for repairs to the damage she had suffered in the Badung Strait. The destroyer Stewart was sufficiently damaged that she had to be dry-docked for repairs in Soerabaja, where she was scuttled to avoid capture by the rapid advance of the Japanese. She was raised, repaired and put into Japanese service a year later as the patrol vessel P-102.