The Serpentine hosts regular triathlon World Cup events
Full plans for the 2012 Olympic triathlon and marathon swim have been submitted with organisers hoping to showcase London's famous landscape.
Both events will be based around the Serpentine in Hyde Park.
The triathlon cycling course will now also go down Constitution Hill and past Buckingham Palace.
London 2012 chairman Sebastian Coe said: "Hyde Park would provide a superb setting for the Olympic triathlon and marathon swimming events."
With the beach volleyball confirmed for Horse Guards Parade in Whitehall, the London Organising Committee (Locog) will be relying on temporary stands and infrastructure at both venues.
Director of sport Debbie Jevons said: "Hyde Park allows us to bring both the triathlon and marathon swim into the city centre - Sydney was the last Olympics to be able to host a triathlon downtown.
"The backdrop will be second to none, and it will allow spectators to get really close to the action."
The triathletes will complete the 1500m swim leg in a single loop around the Serpentine, starting from a pontoon on the north side of the lake, with the 40km bike section split into seven laps and the 10km run broken into four laps of 2.5km.
The 10km marathon swim will consist of six laps of 1.67km - two more than in Beijing in 2008.
Britain's Cassie Patten, who won bronze in Beijing, said: "It will be very special racing in the middle of London - I've got goosebumps thinking about it.
"The six laps will mean more turns, but we'll have to embrace the fact that it's going to be different. Touch wood I'll be out in front."
Horse Guards Parade will see a 15,000-seat temporary arena constructed, with the stands designed to offer a clear view across the central London skyline.
Local residents, Westminster council and the Royal Parks will be consulted this month before the planning applications are submitted in October.
Test events would then be held at both venues in summer 2011, with the temporary structures installed in June 2012, just two months before the Olympics begin.