The UK sovereign bases are those British military base areas located in countries formerly ruled by the United Kingdom which were retained by it and not handed over when those countries attained independence.

Cyprus

Akrotiri and Dhekelia military bases are UK Sovereign Base Areas (SBAs) in Cyprus, a former British Crown Colony. A British garrison force is stationed there to defend them, and they contain a British listening post, and the only fully fledged RAF station in the Mediterranean (since Gibraltar does not have any aircraft permanently based there), RAF Akrotiri. In addition to the garrison, the UK makes a contribution to the United Nations force in Cyprus. In total, some 3,500 British personnel are based in Cyprus.

There is certain disorientation when entering a sovereign base area (unlike Guantanamo Bay, there are roads running through the bases open to traffic from Cyprus). In particular, the road names are all very English, like "Worcester Road". The legal system is administered by the British military, but is pattern on that of the Republic of Cyprus. Many Cypriots work in the SBAs, but they are not permitted to live there. However, the villages of Xylotimbou and Ormidhia, in the Republic of Cyprus, are enclaves surrounded by Dhekelia.

The Sovereign Bases in Cyprus are considered to be an overseas territory, but instead of having a Governor, like other such territories, it has an Administrator, who, while appointed by the Queen, is responsible to the Ministry of Defence, not to the Foreign and Commonwealth Office.

Ireland

After the creation of the Irish Free State (now the Republic of Ireland) in 1922, the UK retained two ports in Queenstown, Ireland (now Cobh) and Berehaven and a base at Lough Swilly. These were handed over to Éire in 1938. Some considered this a short-sighted decision, since following the outbreak of World War II, the British supply routes across the Atlantic Ocean were initially more difficult to protect without these bases, because the convoy escort refuelling facilities which Berehaven and Queenstown would have provided were 200 miles further out into the Atlantic than those which were available in Northern Ireland and England. This became less important after the Allies established bases in Iceland following the British occupation in 1940.