Solomon Islands campaign The Solomon Islands campaign was a major campaign of the Pacific War of World War II . The campaign began with Japanese landings and occupation of several areas in the British Solomon Islands and Bougainville , in the Territory of New Guinea , during the first six months of 1942 . The Japanese occupied these locations and began the construction of several naval and air bases with the goals of protecting the flank of the Japanese offensive in New Guinea , establishing a security barrier for the major Japanese base at Rabaul on New Britain , and providing bases for interdicting supply lines between the Allied powers of the United States and Australia and New Zealand . The Allies , in order to defend their communication and supply lines in the South Pacific , supported a counteroffensive in New Guinea , isolated the Japanese base at Rabaul , and counterattacked the Japanese in the Solomons with landings on Guadalcanal ( see Guadalcanal Campaign ) and small neighboring islands on 7 August 1942 . These landings initiated a series of combined - arms battles between the two adversaries , beginning with the Guadalcanal landing and continuing with several battles in the central and northern Solomons , on and around New Georgia Island , and Bougainville Island . In a campaign of attrition fought on land , on sea , and in the air , the Allies wore the Japanese down , inflicting irreplaceable losses on Japanese military assets . The Allies retook some of the Solomon Islands ( although resistance continued until the end of the war ) , and they also isolated and neutralized some Japanese positions , which were then bypassed . The Solomon Islands campaign then converged with the New Guinea campaign . Background . Strategic background . On December 7 , 1941 , after failing to resolve a dispute with the United States over Japan ' s actions in China and French Indochina , the Japanese attacked the US Pacific fleet at Pearl Harbor , Hawaii . The attack crippled most of the U . S . Pacific Fleet ' s battleships and started a formal state of war between the two nations . Attacks on British Empire possessions in the Pacific , beginning with an attack on Hong Kong almost simultaneous with the Pearl Harbor attack , brought the United Kingdom , Australia and New Zealand into the conflict . In launching this war , Japanese leaders sought to neutralize the U . S . fleet , seize possessions rich in natural resources , and obtain strategic military bases to defend their far - flung empire . In the words of the Japanese Navy ' s Combined Fleet Secret Order Number One , dated November 1 , 1941 , the goals of the initial Japanese campaigns in the impending war were to , " ( eject ) British and American strength from the Netherlands Indies and the Philippines , ( and ) to establish a policy of autonomous self - sufficiency and economic independence . " The Empire of Japan accomplished its initial strategic objectives in the first six months of the war , capturing the Philippines , Thailand , Malaya , Singapore , the Dutch East Indies , Wake Island , New Britain , Gilbert Islands , and Guam . A Japanese goal was to establish an effective defensive perimeter from British India on the west , through the Dutch East Indies on the south , and to island bases in the south and central Pacific as its southeastern line of defense . Anchoring its defensive positions in the South Pacific was the major Japanese army and navy base at Rabaul , New Britain , which was captured in January 1942 . In March and April , Japanese forces occupied and began constructing an airfield at Buka in northern Bougainville , as well as an airfield and naval base at Buin , in southern Bougainville . Japanese advance into the Solomons . In April 1942 , the Japanese army and navy together initiated Operation Mo , a joint plan to capture Port Moresby in New Guinea . Also part of the plan was a navy operation to capture Tulagi in the southern Solomons . The objective of the operation was for the Japanese to extend their southern perimeter and to establish bases to support possible future advances to seize Nauru , Ocean Island , New Caledonia , Fiji , and Samoa and thereby cut the supply lines between Australia and the United States , with the goal of reducing or eliminating Australia as a threat to Japanese positions in the South Pacific . The Japanese Navy also proposed a future invasion of Australia , but the army answered that it currently lacked enough troops to support such an operation . Japanese naval forces successfully captured Tulagi but its invasion of Port Moresby was repulsed at the Battle of the Coral Sea . Shortly thereafter , the Japanese navy established small garrisons on the other northern and central Solomon Islands . One month later , the Japanese Combined Fleet lost four of its fleet aircraft carriers at the Battle of Midway . The Allies countered the threats to Australia by a build - up of troops and aircraft , with the aim of implementing plans to approach and reconquer the Philippines . In March 1942 Admiral Ernest King , then Commander - in Chief of the U . S . Fleet , had advocated an offense from New Hebrides through the Solomon Islands to the Bismarck Archipelago . Following the victory at Midway , General Douglas MacArthur , who had taken command of the South West Pacific Area , proposed a lightning offense to retake Rabaul , which the Japanese were fortifying and using as a base of operations . The United States Navy advocated a more gradual approach from New Guinea and up the Solomon Island chain . These competing proposals were resolved by Admiral King and U . S . Army Chief of Staff General George C . Marshall , who adopted a three - task plan . Task One was the capture of the island of Tulagi in the Solomons . Task Two was an advance along the New Guinea coast . Task Three was the capture of Rabaul . Task One , implemented by a directive of the Joint Chiefs of Staff on 2 July 1942 and named the initial attacks Operation Watchtower , became the Solomon Islands campaign . Course of campaign . The Allies created a combined air formation , Cactus Air Force , establishing air superiority during the daylight hours . The Japanese then resorted to nightly resupply missions which they called " Rat Transportation " ( and the Allies called " the Tokyo Express " ) through New Georgia Sound ( " The Slot " ) . Many pitched battles were fought trying to stop Japanese supplies from getting through . So many ships were lost by both sides during the Guadalacanal campaign that the southern end of New Georgia Sound , the area north of Guadalcanal previously called Savo Sound , became known as " Ironbottom Sound " . Allied success in the Solomon Islands campaign prevented the Japanese from cutting Australia and New Zealand off from the U . S . Operation Cartwheel — the Allied grand strategy for the Solomons and New Guinea campaign s — launched on June 30 , 1943 , isolated and neutralized Rabaul and destroyed much of Japan ' s sea and air supremacy . This opened the way for Allied forces to recapture the Philippines and cut off Japan from its crucial resource areas in the Netherlands East Indies . The Solomons campaign culminated in the often bitter fighting of the Bougainville Campaign , which continued until the end of the war .