The USS S-27 was a submarine of the United States Navy, part of the S-class fleet. Launched on March 1, 1919, it was designed for coastal defense and operated primarily in the Pacific Ocean. The submarine was 219 feet long and had a surface displacement of around 850 tons. During its service, the USS S-27 conducted various training exercises and patrols. It was commissioned on December 1, 1922, and decommissioned on June 30, 1931. The submarine was ultimately sold for scrap in 1934, marking the end of its operational life.