|Builder||Union Iron Works, San Francisco, California|
|Laid down||22 March 1911, as Seawolf|
|Launched||6 May 1913|
|Commissioned||1 December 1913|
|Renamed||H-1, 17 November 1911|
|Stricken||12 April 1920|
|Length||150 ft 4 in (45.82 m)|
|Beam||15 ft 10 in (4.83 m)|
|Draft||12 ft 5 in (3.78 m)|
|Test depth||200 ft (61 m)|
|Complement||25 officers and men|
|Armament||4 × 18-inch (450 mm) torpedo tubes (8 × torpedoes)|
Seawolf was laid down by the Union Iron Works of San Francisco, California. She was renamed on 17 November 1911, launched on 6 May 1913 sponsored by Miss Lesley Jean Makins, and commissioned at Mare Island Navy Yard on 1 December 1913.
The new submarine was attached to Torpedo Flotilla 2, Pacific Fleet, and operated along the West Coast out of San Pedro, California. During various exercises and patrols, she traveled the coast from Los Angeles, California to lower British Columbia, often in company with her sister ships H-2 and sometimes H-3.
Sailing from San Pedro, California on 17 October 1917, she reached New London, Connecticut on 8 November. For the remainder of World War I, she was based there and patrolled Long Island Sound, frequently with officer students from the submarine school on board.
H-1 and H-2 sailed for San Pedro, California on 6 January 1920, transiting the Panama Canal on 20 February. On 12 March, as H-1 made her way up the coast of Mexico's Baja California Peninsula, she ran aground on a shoal off Magdalena Bay.
Four men – including the commanding officer died trying to reach shore. Vestal pulled H-1 off the rocks in the morning of 24 March, but in only 45 minutes, the submarine sank in some 50 ft (15 m) of water. Further salvage effort was abandoned. Her name was stricken from the Naval Vessel Register on 12 April, and she was sold for scrap in June 1920, but never recovered.
- "Hallan submarino de la Primera Guerra Mundial en las costas de México" [First World War submarine found off the coast of Mexico], CNN en Espanol (in Spanish), September 5, 2019, retrieved September 5, 2019