Battle of Tarakan ( 1942 ) The Battle of Tarakan took place on January 11 – 12 , 1942 , beginning a day after Japan declared war on the Kingdom of the Netherlands . Although Tarakan was only a small marshy island off northeastern Borneo in the Netherlands East Indies , the island ' s 700 oil wells , oil refinery , and airfield made it a crucial objectives for the Empire of Japan in the Pacific War . Geography . Tarakan is a triangle shaped island off the coast of Borneo . The island is roughly long from its northernmost point to the southern tip and wide towards the north of the island . The small island of Sadau is located about off Tarakan ' s west coast . Almost all of Tarakan ' s coastline is swampy , and in 1945 mangrove s on the northern half of the island stretched to inland . The coastal mangroves in the southern portion of the island were narrower . Inland from the swamps , most of central Tarakan comprised a series of steep and densely forested hills just over high . Tarakan is located three degrees north of the equator and has a tropical climate . The maximum temperature for most days is about 90 degrees Fahrenheit , and relative humidity is consistently high at about 90 % . In 1945 , Tarakan Town was the main settlement of the island . This town was located inland , and was separated from the south - west coast by several small hills covered in low vegetation . Four piers used to dock oil tankers were located on this coastline , and were connected to Tarakan Town by three surfaced roads . Tarakan airfield was located about north - west of Tarakan Town . Of the island ' s two oilfields , Sesanip Oilfield was located at the north - east edge of the airfield while the larger Djoeata or Juata Oilfield was to the north . The village of Djoeata was located on Tarakan ' s north - west coast and linked to Djoeata Oilfield by a track . The Japanese landing . On January 10 , 1942 , after a Dutch Dornier Do 24K flying boat spotted an approaching Japanese invasion fleet , the commander of Tarakan ' s garrison ordered the destruction of all oil installations on the island . The Japanese forces of the " Right Wing Unit " from the " Sakaguchi Detachment " landed on the east coast of Tarakan at midnight on January 11 , 1942 , followed by the " 2nd Kure Special Naval Landing Force " . After mounting brief , but fierce resistance , the heavily outnumbered " Koninklijk Nederlands Indisch Leger " ( Royal Netherlands East Indies Army , or KNIL ) garrison surrendered in the morning of January 12 . All prisoners of war were executed by the Japanese via drowning in retaliation for the destruction of the oil installations , an action that was repeated later following the Battle of Balikpapan . During the night of January 11 , before Japan completed the blockade of Tarakan , the Dutch submarine " K - X " , the patrol boat " P - 1 , " and the civilian motor launch " Aida " slipped away . The Dutch minelayer " Prins van Oranje " tried to escape as well but was sunk by the Japanese destroyer " Yamakaze " , under Lt . Cdr Shuichi Hamanaka , and the patrol boat " P - 38 " . Dutch planes flew bombing missions from an airfield in eastern Borneo ( called Samarinde II ) in order to attack Japanese ships . Tarakan remained under Japanese occupation until May 1945 , when it was liberated by Australian troops in the 1945 Battle of Tarakan . Order of battle . Ground forces . Japanese Units . Sakaguchi Detachment Dutch Units . Tarakan Garrison