Battle of Christmas Island The Battle of Christmas Island was a small engagement which began on 31 March 1942 , during World War II . Because of a mutiny by Indian soldiers against their British officers , Japanese troops were able to occupy Christmas Island without any resistance . However , the American submarine caused severe damage to the Japanese cruiser . Background . At the time , Christmas Island was a British possession under administrative control of the Straits Settlement , situated south of Java . It was important for two reasons : it was a perfect control post for the east Indian Ocean and it was an important source of phosphate s , which were needed by Japanese industry . After the occupation of Java , Japanese Imperial General Headquarters issued orders for " Operation X " ( the Invasion and Occupation of Christmas Island ) on 14 March 1942 . Rear Admiral Shōji Nishimura was assigned to command the Second Southern Expeditionary Fleet ' s Occupation Force , with the light cruiser as his flagship . The fleet also consisted of the light cruisers and , and destroyer s , , , , , , and , oiler " Akebono Maru " and transports " Kimishima Maru " and " Kumagawa Maru " , with 850 men of the 21st and 24th Special Base Forces and the 102nd Construction Unit . Opposing this invasion force was an old gun brought down from Singapore after World War I , and possibly up to three anti - aircraft gun s . The British garrison — a detachment of the Hong Kong and Singapore Royal Artillery — numbered 32 , mostly Indian troops led by a British officer and four British NCOs . The Indian troops , apparently believing Japanese propaganda concerning the liberation of India from British rule , mutinied and killed their sleeping British superiors on 10 March 1942 , then locked up the District Officer and the few other European inhabitants of the island pending an execution that apparently was thwarted by the Japanese occupation . Battle . At dawn on 31 March 1942 , a dozen Japanese bombers launched the attack , destroying the radio station , which stood roughly where the post office is today . Fragments of bombs dropped were still being found into the 1980s in the Post Office Padang . Because of the mutiny , the Japanese expeditionary corps was able to disembark at Flying Fish Cove without opposition . At 09 : 49 the same morning , the American submarine fired four torpedoes at the " Naka " ; all missed . " Seawolf " attacked again at 06 : 50 the following morning , firing three torpedoes at " Natori " , missing again . That evening , with her final two torpedoes , from , " Seawolf " managed to hit " Naka " on her starboard side , near her No . 1 boiler . The damage was severe enough " Naka " had to be towed back to Singapore by " Natori " , and eventually was forced to return to Japan for a year of repairs . Following the hit , the other Japanese vessels depth charged the American submarine for over seven hours but it escaped . " Natori " returned to Christmas Island and withdrew all elements of the occupation force with the exception of a 20 - man garrison detachment to Banten Bay on 3 April 1942 . All that the Japanese had gained was the phosphate rock which was loaded on the transport ships . After the war seven mutineers were traced and were prosecuted by a Military Court in Singapore and five were sentenced to death in 1947 . The sentences were commuted to life imprisonment after the governments of India and Pakistan made representations .