H.M.S. Seahorse, a 38-gun frigate, was ordered by the Admiralty on February 2, 1793, laid down in March 1793, launched on June 11, 1794, and completed in September 1794 at Deptford. She was commissioned in July 1794, Captain John Peyton in command.

Early in her career, operating in home waters and off the coast of Europe, she took part in the capture of the privateers Calvados (July 1796) and L'Indemnité (August 28, 1796), as well as the Princesa (September 16, 1796), before sailing for the Mediterranean early in 1797. Later in the year, while under the command of Captain Thomas Fremantle, she took part in Horatio Nelson's failed assault at the Battle of Santa Cruz de Tenerife (July 22-25, 1797). Returning to the Mediterranean in March 1798, she served with Samuel Hood's squadron off Alexandria, Egypt in August, and was present when the French garrisons at Naples surrendered in June 1799. After grounding off Livorno, Italy in July of that year, she returned home in October before sailing back to the Mediterranean as Rear Admiral Richard Bickerton's flagship in May 1800.

Following repairs at Portsmouth, England in the spring of 1803, she was recommissioned in May of that year, under the command of Captain Courtnay Boyle, for action during the Napoleonic Wars. Spending much of her time in the Mediterranean, she captured a store ship at San Pedro (May 4, 1805), Badere-i-Zeffee (May 7, 1807), and the privateer La Stella di Napoleon (May 5, 1810), as well as sinking the Aziz Fezzan (May 7, 1807).

Undergoing repairs in 1812, Seahorse was recommissioned in September 1812, under the command of Captain Sir James Gordon. In November, she sailed for North America for action during the War of 1812, and was engaged in the Potomac River at the time of the burning of Washington in August 1814. Returning to Portsmouth, England, she was laid up in September 1815, and was broken up there four years later, in July 1819.