Parkour professionals leap-frogged their way across the Royal Docks to launch the second River Rat Race alongside charity Shelter.
The trio hopped, skipped and jumped across the waters - briefly touching down on pontoons - to promote the 10km water-based obstacle race on July 25.
Competitors will set off from the Excel and tackle a quick-fire barrage of obstacles including a zorb pool, trampolines and a 50ft slide during a group attempt to raise £50,000 to battle homelessness in the capital.
They will also brave the splashes - and heights - during wading, kayaking and a 20ft jump from the dock.
Rat Race MD and creator of The River Rat Race Jim Mee said: “We are delighted to be returning to London for the River Rat Race 2015.
“At 10km, the course provides a good fitness challenge, but the water elements make it a lot of fun, especially when the sun comes out.”
Entry costs £65 plus a £10 standard donation to Shelter.
Go to ratrace.com .