Argentine troops invading the island on April 2, 1982
A single candle is to be lit at Britain's National Arboretum to mark the 30th anniversary of the start of the Falklands War, reports the BBC.
Argentina invaded the islands, which it calls the Malvinas, on April 2, 1982.
The UK responded by sending a taskforce to regain the Falklands. More than 250 British and 649 Argentine troops died.
UK Prime Minister David Cameron will mark the anniversary by telling the Falkland islanders he remains committed to upholding British sovereignty.
The anniversary of the invasion falls against a backdrop of renewed tension over the islands, with Argentina reiterating its claim to the archipelago.
Britain has controlled the Falklands since 1833 but Argentina claims the territory, saying it inherited its rights to them from Spain.
Argentina has asked for negotiations about sovereignty but the British government says they will not do so without the agreement of the islanders.
London has also accused Buenos Aires of trying to impose an economic blockade on the islanders, after it banned Falklands-flagged ships from docking in its ports, as well as those of other countries which are members of the Mercosur trading block.
Argentina has also complained about what it calls British "militarisation" in the south Atlantic, after one of the Royal Navy's newest warships was deployed to the region.
The BBC's World affairs editor, John Simpson, said while a new armed conflict remains unlikely, Argentina is now using diplomatic weapons to push its claim over the Falklands.
Argentina's President Cristina Fernandez de Kirchner is expected to visit the southern port of Ushuaia on Monday, to remember the Argentine troops that died.
President Fernandez is expected to lead rallies to commemorate the Argentine dead and light an eternal flame.
Prior to her arrival, Argentine veterans held a vigil for the fallen.
Cameron is expected to sound a conciliatory tone by suggesting the anniversary be used to remember the Argentine dead as well as British losses.
In a speech he will say: "Thirty years ago today the people of the Falkland Islands suffered an act of aggression that sought to rob them of their freedom and their way of life.
"Today is a day for commemoration and reflection: a day to remember all those who lost their lives in the conflict - the members of our armed forces, as well as the Argentinian personnel who died."
Cameron will salute the "heroism" of the soldiers, sailors, airmen and marines who took part in the operation which freed the islanders from Argentine rule.
He will say: "We are rightly proud of the role Britain played in righting a profound wrong. And the people of the Falkland Islands can be justly proud of the prosperous and secure future they have built for their islands since 1982.
"Britain remains staunchly committed to upholding the right of the Falkland Islanders, and of the Falkland Islanders alone, to determine their own future.
"That was the fundamental principle that was at stake 30 years ago: and that is the principle which we solemnly reaffirm today."
The defeat of the Argentine forces led directly to the collapse of the military dictatorship led by Gen Leopoldo Galtieri, who was later jailed in Buenos Aires for "incompetence" during the war.
The British prime minister at the time was Margaret Thatcher but she is not expected to play a part in the commemoration of the 30th anniversary.