'IG' was the designation of Allied convoys (together with a numerical suffix) plying the route from the Philippine islands group to New Guinea, and as such reciprocals of the 'GI' series (January/March 1945).

The first known convoy of this series, which was associated largely with 'Mike I' and the first stage of the reconquest of Luzon, was IG.5 of 27 January/2 February 1945 from Leyte to Hollandia with 12 US ships in the form of Allen Johnson, 7,279-ton Copiapo, 11,615-ton E. J. Henry, 10,296-ton Esso Roanoke, 6,165-ton Fairisle, 7,176-ton Nicholas J. Sinnott, 10,195-ton Seven Pines, William I. Chamberlain, and the commissioned fleet tug Apache, cargo ship Murzim minesweeper Vireo and auxiliary ocean tug ATA-176.

The last of the series was IG.102 of 3/13 March 1945 from Lingayen to Hollandia with 23 US ships in the form of the 7,180-ton Alexander J. Dallas, 7,194-ton Benjamin Bonneville, Edward S. Hough, George B. McFarland, 1,169-ton Hains, 7,176-ton Jacques Cartier, 7,176-ton James Ives, 7,176-ton James J. O’Kelly, 7,180-ton Lindley M. Garrison, 7,176-ton Margaret Fuller, McKittrick Hills, 7,176-ton Nathaniel Currier, Robert F. Broussard, 10,448-ton Stony Point, Walter Wyman, 7,244-ton William N. Pendleton, and commissioned petrol tanker Agawam, station tanker Andrew Doria, fleet tug Apache, station tanker Stag, and US Army coastal freight and supply ships FS-44, FS-47, FS-78 and FS-195.