Nick Christoforou, 31, and Sophia Toon, 23, ordered a car from the popular driving app at 1.30am.
While the pair, who were on a work trip, were in the car, it went off the end of a jetty and into the French Riviera.
Christoforou, a real estate agent from Cockfosters in north London, managed to open a door and, along with the driver, all three swam to safety.
Had it not been for his actions they “would all be 100% dead”, Christoforou told The Sun.
The ride-hailing app reportedly still charged him for the trip, although the fare has since been refunded.
“One minute I was in the back of an Uber heading home, and the next I was in the sea,” he said.
“I managed to get the car door open and got to the surface to find the others.
“If I wasn’t in a fit and able state we would all be 100% dead.”
Images showed the Citroen DS5 partially submerged in 10ft of water at Port Pierre Canto.
The driver was breathalysed and found to be sober, the paper said.
A police spokesman told The Sun the car had sunk slowly, giving them time to escape.
An Uber spokeswoman told the paper: “We contacted both passengers to ensure they were OK and are offering counselling while they await the outcome of their (insurance) claim.
“The driver involved is no longer able to use the Uber app.”