R-1 (Submarine No. 78) was laid down 16 October 1917 by the Fore River Shipbuilding Co., Quincy, Mass.; launched 24 August 1918; sponsored by Mrs. George W. Dashiell; and commissioned 16 December 1918 at Boston, Comdr. Conant Taylor in command.
After shakedown in New England waters, R-1 was assigned to Submarine Division 9 of the Atlantic Fleet and based at New London, Conn. She got underway 4 December 1919 for Norfolk and winter exercises with her division in the Gulf of Mexico, and returned to New London 18 May 1920 for 4 months of summer operations with R-2 (SS-79) and R-3 (SS-80) before sailing 13 September for Norfolk and overhaul.
Designated SS-78 in July 1920, R-1 was ordered to the Pacific 11 April 1921, transited the Panama Canal in late May, and arrived on 30 June at her new base, San Pedro, Calif. She took part in fleet exercises off Central America from 5 February through 6 April 1923; returned to San Pedro on 10 April, and on 16 July was transferred, along with Division 9, to Pearl Harbor where for the next 8 years she trained crews and developed submarine tactics.
Departing San Diego 5 January 1931, R-1 sailed for Philadelphia via the Panama Canal; arrived 9 February and was decommissioned there 1 May 1931. She was recommissioned in ordinary 23 September 1940 at Groton, Conn., overhauled and commissioned in full 16 October. R-1 got underway with Submarine Squadron 3, Division 42 on 10 December for the Panama Canal Zone. Stationed at Coco Solo for a year, she was reassigned to Division 31 in June 1941, ordered to New London in October for a refit, and transferred to Squadron 7.
At New London on 7 December 1941, R-1 remained in the southern New England area for the first days of American participation in World War II. On the 9th and 10th she patrolled the sealanes leading to New England and on the 11th arrived at Bermuda, whence, with other SubRon 7 boats, she joined the hunt for U-boats preying on maritime traffic along the North American coast. Although limited in cruising range, the R-boats operating out of Ordnance Island, continued their patrols through the Nazi submarine offensive of early 1942.
In February, the submarines established a patrol line between Bermuda and Nantucket Island. On that patrol line, some 300 miles northeast of Bermuda, R-1 sighted, attacked, and probably damaged a surfaced U-boat on 16 April.
R-1 continued patrols out of Bermuda until returning to New London 20 July for upkeep and coastal patrols. At the end of September, she resumed operations out of Bermuda. Through November 1944 she rotated between Bermuda and New London and, at the latter, in December underwent an extensive conversion to enable her to participate in the development of ASW equipment and tactics. Emerging from the yard 26 February 1945, she steamed to New York on the 28th; then headed south to Florida for 3 weeks of operations off Port Everglades. In April she returned to New London, thence steamed to Casco Bay for further ASW tests. Returning to the Thames River base 29 June, she headed south again 7 July and at midmonth reported for duty with the Fleet Sonar School at Key West, where she served for the remainder of her career.
R-1 decommissioned at Key West 20 September 1945 and was struck from the Navy list 10 November. Still at Key West awaiting disposal on 21 February 1946, the overage submarine sank in 21 feet of water. Raised 3 days later, she was sold for scrap 13 March 1946 to Macey O. Smith of Miami.