The Guadalcanal Campaign was fought between August 7 , 1942 , and February 9 , 1943 , in the Pacific theater of World War II . The Guadalcanal Campaign , also known as the Battle of Guadalcanal and codenamed Operation Watchtower by Allied forces , was fought between August 7 , 1942 and February 9 , 1943 on and around the island of Guadalcanal in the Pacific theater of World War II .