A service of thanksgiving marked the occasion, held at Christ Church Cathedral in Port Stanley, followed by a military parade to the Liberation Monument led by veterans of the 1982 conflict, the BBC reported.
Prime Minister David Cameron expressed Britain's support for the islands, which had "not wavered in the last 30 years and it will not in the years ahead."
The Falklands government announced it would hold a referendum on its political status, emphasizing islanders wanted to remain British.
Britain liberated the islands June 14, 1982, after 74 days of Argentine occupation. About 225 British servicemen, three Falklands civilians and 650 Argentines were killed in the armed conflict that ensued after Argentina invaded in an attempt to reclaim the islands.
Despite the defeat, Argentina still claims sovereignty over the islands.
Britain has laid claim to the Falklands since the Royal Navy expelled Argentina in 1833 when it re-established its status as a U.K. territory.