Accompanied by smaller crafts and patrol boats, the Royal Navy’s largest ship has travelled up the capital’s river before berthing at Greenwich in east London.
From there, it will house eight Lynx helicopters and become a base for Royal Marine snipers during the Olympic Games.
At 38 metres wide, the crew of HMS Ocean will have to negotiate a complicated 180-degree turn as it reaches its destination.
The warship’s journey is the final phase of the exercise named Olympic Guardian, as London finalises its security plans ahead of this summer’s Games.
Prior to guiding the vessel through “challenging” gaps of just 60 metres, Captain Andrew Bretton said the ship would focus on air security over the weekend, with river operations taking place between Tuesday and Thursday next week.
At 38 metres wide, the crew of HMS Ocean will have to negotiate a complicated 180-degree turn as it reaches its destination.
"That will stretch all elements of Ocean's contribution to the security plan, and then I hope assure the security organisation that we are ready to provide the envelope required for the Olympic Games themselves," he said.
HMS Ocean spent four months operating off the Libyan coast last year, as British forces engaged in the downfall of Colonel Gadaffi.