After being commissioned, ENS Adamson became a student at the Naval Air Station in Jacksonville, Florida. Following his schooling, ENS Adamson reported in September 1943 for duty aboard the . The USS "San Diego" joined the USS "Saratoga" in support of the invasion of Munda, New Georgia, and of Bougainville. Then supported the Bombing of Rabaul in November 1943. Ens Adamson aboard the USS Diego then took part in Battle of Tarawa 20–23 November 1943. She then escorted the USS "Lexington" back to Pearl Harbor for repairs. On 6 January 1944 the USS "San Diego" became part of Task Force 58 under command of Rear Admiral Marc Mitscher. Adamson then took part in Operations Flintlock and the Battle of Tarawa. The "San Diego" had some improvements made on her radar in San Francisco and headed back into the fight joining in on raids against Wake and Marcus Islands, the invasion of Saipan, the Battle of the Philippine Sea, the invasion of Guam and Tinian, and the first raids against the Philippines.