Gibbs Technologies, who made the car, say this is the first time a car-boat has managed to get above 6 miles per hour.
It can go so fast because, when it's a boat, it's powered by a jet of water.
The Amphibian is meant to be a sports car and sports boat, but it could even be used in cities to cut traffic.
But you'd have to be pretty rich to afford one - when it comes out later this year, it should cost around £150,000.
Perhaps James Bond will have the river to himself for a little while longer after all.