USS S-30 (SS-135) was an S-class submarine of the United States Navy during World War II. Construction and commissioning S-30 was laid down on 1 April 1918 by the Union Iron Works at San Francisco, California. She was launched on 21 November 1918, sponsored by Mrs. Edward S. Stalnaker, and commissioned on 29 October 1920. Service history 1920–1941 Based at San Pedro, California, with her home yard at Mare Island, California, S-30 conducted tests and exercises off the California coast until the summer of 1921. Then, on 15 August 1921, she was placed in ordinary. Returned to full commmission on 14 February 1922, she was ordered to New London, Connecticut, where she was placed in ordinary again on 21 June 1922 for engine alterations by the prime contractor for her construction, the Electric Boat Company. Trials and exercises off the southern New England coast followed her return to full commission on 21 November 1922. In January 1923, she moved south to the Caribbean Sea to participate in winter maneuvers and Fleet Problem I, conducted to test the defenses of the Panama Canal Zone. In April 1923, she returned to California and resumed operations off the coast of California with her division, Submarine Division 16. During the winter of 1924, she again participated in fleet exercises and Fleet Problems in the Panama Canal Zone area and in the Caribbean. During the winter of 1925, S-30 prepared for transfer to the United States Asiatic Fleet. She departed Mare Island with her division in mid-April 1925. During May 1925, she conducted exercises and underwent upkeep in the Hawaiian Islands, and, on 16 June 1925 she got underway for the Philippines. On 12 July 1925, she arrived at the Submarine Base, Cavite, Luzon. In the years that followed, her division rotated between exercises and patrols in the Philippines during the winter and operations off the China coast during the summer. In 1932, S-30′s division was ordered back to the eastern Pacific Ocean, and, on 2 May 1932, she departed Manila bound for Pearl Harbor, Hawaii, which became her new home port. Transferred back to the United States East Coast, S-30 departed Pearl Harbor on 19 May 1937 and arrived at New London on 8 August 1937. She then trained along the U.S. East Coast until May 1939, when she was placed in commission, in reserve. On 1 September 1940, she returned to full commission.