[4][5] Due to the lack of destroyers in the Franco's fleet, and the potential of their armament, the main mission of these vessels was not minelaying, but to face Government units in open combat, despite their slow speed.

[4] Along with Vulcano, Júpiter was one of the main players in the blockade of international shipping in the ports of Biscay, where she took part in the capture of several merchantmen, especially the British Candleston Castle, Dover Abbey and Yorkbrook, the French Cens and a number of Basque Auxiliary Navy trawlers during the second half of 1937.

[12] On 5 October, while she was escorting the seized freighters Dover Abbey and Yorkbrook to Ribadeo, the former vessel sent a distress message to HMS Resolution, giving the position and course of the convoy and claiming that her capture had taken place outside territorial waters.

[13] At least five minor vessels carrying refugees and soldiers of the Republican army where seized by the minelayer after the fall of the last government's strongholds on northern Spain by the end of October.

[15][16][17] Towards the end of the war, along with the auxiliary cruiser Mar Negro, she supported the landing of an infantry division on Mahón, Menorca, after the Republican surrender of this island, on 9 February 1939.

Assisted by her sister ships, Júpiter entered the port on 31 March, the day before the official end of the conflict, in order to land the 121st and 122nd Galician Regiments.

[22] At the end of the war in the north she joined a naval squadron which drove back the steamers Hillfern, Bramhill, Stanhill and Stanleigh off Cape Peñas, seizing a number of small Republican vessels crowded with refugees in the process.

[17] She played a key role, along with her sisters ships, in ferrying troops after Franco's army reach the coast between Valencia and Barcelona in April 1938.

She also played a secondary role in the capture of the Greek merchant Victoria by the auxiliary cruiser Mar Cantábrico and the British Stangrove by the gunboat Dato, in the final months of the civil war.

[25] Perhaps the most famous action of Vulcano is the chase and capture of the Republican Churruca-class destroyer José Luis Díez off Gibraltar, in the course of a battle fought as close as 50 metres (160 ft) between the ships involved.

The minelayer departed from El Ferrol in December 1938 to take part in the chase of the Republican destroyer José Luis Díez, which had taken shelter in Gibraltar.

Later, in January 1939, while based at the port of Palma, Marte participated in gunnery trials off Majorca and in blockade activities along the Catalan coast and the Gulf of Lion.

[31][32] The Stanbrook eventually reached the Spanish port on 27 March,[33] after the Nationalist side displayed some indulgency toward the evacuation of refugees in return for the British recognition of Franco's legitimacy.

Her Welsh skipper, Captain Archibald Dickson, later killed during the sinking of his ship in World War II, is today remembered as a hero in Alicante.

Júpiter was written off the Navy List on 23 November 1974, and Vulcano was used as a store ship from 12 March 1977 until her final decommissioning on 30 April 1978, this being the last warship to be removed from service of those who participated in the Civil War.