Tinian Naval Advanced Base was a major United States Navy sea and air base on Tinian Island, part of the Northern Mariana Islands on the east side of the Philippine Sea in the Pacific Ocean. The base was built during World War II to support bombers and patrol aircraft in the Pacific War. The main port was built at the city and port of San Jose, also called Tinian Harbor. All construction was carried out by the Navy's Seabees 6th Naval Construction Brigade, including the main two airfields: West Field and North Field, serving the United States Army Air Forces's long-range Boeing B-29 Superfortress bombers. The Navy disestablished the Tinian Naval Advanced Base on 1 December 1946.