Juno was ordered on 21 October 1778 and laid down in December that year at the yards of the shipbuilder Robert Batson & Co, of Limehouse.

On 10 February 1781 Juno and the sloop Zebra captured the American privateer Revanche (or Revenge) off Beachy Head.

[3] Montagu then sailed the Juno in early 1782 to join Richard Bickerton's squadron operating in the East Indies.

[1] Hood initially cruised in the English Channel after the outbreak of the French Revolutionary Wars, capturing the privateers Entreprenant on 17 February, Palme on 2 March and, together with HMS Aimable, Laborieux in April.

[6][7] On being informed that British forces had left and that he and his ship's company were now prisoners of war, Captain Hood ordered cables to be cut and immediately set sail with the 13 French officials aboard as prisoners, whereupon Juno received a broadside from a nearby brig and came under point-blank fire from French batteries, but was able to escape with only light damage.

[5] On 7 February 1794 Juno and the 74-gun HMS Fortitude carried out an attack on a tower at Mortella Point, on the coast of Corsica.

[8] Captain Lord Amelius Beauclerk succeeded Hood, who returned to Britain with a convoy in October 1795, and paid her off in January the following year.

MacKenzie put Lieutenant Salusbury Pryce Humphreys of Juno on the captured schuyt after arming her with two 12-pounder carronades and naming her the Undaunted.

[16] On 8 September Juno was eight leagues off Cape Sparivento when she captured the French bombarde privateer Quatre Fils, of Nice.

[17] In 1805 Juno and several other frigates and sloops arrived at Gibraltar where Nelson employed them to harass coastal shipping that was resupplying the Franco-Spanish fleet at Cadiz.

[4] When Smith had arrived in Palermo on 21 April 1806 he found that Gaeta still held out against the French even though the Neapolitan government had had to cede the capital.

The Prince of Hesse-Philipstad put 60 men from the garrison at Gaeta in four fishing-boats and on the night of 12 May Richardson took them and the boats from Juno and Minerva to a small bay in the French rear.

In 1809 it became a duché grand-fief in the Napoleonic Kingdom of Naples, but under the French name "Gaete", for finance minister Martin-Michel-Charles Gaudin.

Captain Granville Proby replaced Schomberg in July that year, with orders to sail Juno back to Britain.