A SUCCESSFUL day spent exploring the Maroochy River on the back of a jetski came to a bad end for this ute driver.

The unidentified man was hooking up his jetski to the back of his ute at the Fishermans Rd boat ramp yesterday when he was forced to jump out of the path of his vehicle.

Caloundra man Danny McKie believes the handbrake could have given way and the ute rolled down the ramp and into the river.

The river slowly swallowed the blue Nissan Navara dual cab.

Mr McKie was working when he spotted the car sunk up to its roof.

"I think he was trying to put his jetski up on the tray of his ute and I don't know what happened but he had to jump out of the way before the ute went for a swim," Mr McKie said.

"He wasn't happy about it, that's for sure."

A tow truck was called to pull the car out of the water.