Largest Nuclear Submarine in the US Navy Makes Rare Visit to Gibraltar

The Largest Submarine in the US Fleet

The USS Alaska (SSBN-732), an Ohio-class ballistic missile submarine, docked at the South Mole of Naval Base Gibraltar on the evening of May 10 under exceptional security. At 170.7 metres in length and with a submerged displacement of 18,750 tonnes, Ohio-class boats are the largest submarines in the entire US Navy.

The vessel is armed with 20 Trident II D5 ballistic missiles — each with a range exceeding 7,000 nautical miles and capable of carrying multiple nuclear warheads — as well as four Mk-48 ADCAP torpedoes. It is powered by an S8G pressurised-water nuclear reactor.

Tight Security Operation

Royal Marines were specially flown in by RAF transport aircraft ahead of the arrival — an unusual mobilisation. Naval units from the Royal Navy's Gibraltar Squadron, the Gibraltar Defence Police, and Royal Marines guided the vessel through the Strait of Gibraltar, with two tugboats assisting docking. A 200-metre maritime exclusion zone was established around the berth. No departure date has been publicly disclosed.

Only the Third Such Visit in 25 Years

This is only the third publicly observed US Ohio-class submarine visit to Gibraltar in approximately 25 years. The USS Alaska itself previously docked here in June 2021. Other Ohio-class boats — USS Florida, USS Rhode Island and USS Georgia — visited in 2022, prompting a formal protest from Spain's Foreign Office at the time.

A Diplomatic Snub to Rota?

Gibraltar sits just 141 kilometres from the US Naval Station Rota in Spain — one of the most strategically important US military facilities in Europe. Spain maintains that its Rota base has special protocols governing nuclear submarine visits, and the choice of Gibraltar over Rota is being interpreted in some quarters as a deliberate diplomatic signal.

The visit comes against a backdrop of severely strained US-Spain relations: Prime Minister Pedro Sánchez refused to allow US military bases in Spain to participate in any operations against Iran, to which President Trump responded by threatening trade measures and a potential withdrawal of the approximately 3,800 US troops stationed in Spain.

The Iran Backdrop

The timing is significant. The USS Alaska's arrival coincided directly with President Trump publicly rejecting Iran's response to a US ceasefire and nuclear framework proposal. Gibraltar controls the only Atlantic-Mediterranean passage, giving submarines rapid access to the Eastern Mediterranean and the Suez Canal — a strategic asset in any scenario involving Iran or the Hormuz Strait.

Spanish environmental group Verdemar Ecologistas en Acción criticised the visit, calling it "military servitude" and citing environmental risks from nuclear submarines transiting the Strait of Gibraltar.

This article is based on reporting from The Olive Press, published May 11, 2026.