The USS S-43 was a United States Navy submarine, part of the S-class fleet. Launched on March 24, 1926, it was designed for coastal defense and reconnaissance missions. The submarine was 219 feet long and had a surface displacement of around 1,000 tons. During its service, the USS S-43 operated primarily in the Pacific Theater, conducting training exercises and patrols. It was decommissioned on June 30, 1945, and later sold for scrap in 1946. The submarine is notable for being one of the many vessels that contributed to the U.S. Navy's capabilities during World War II.