This is the dramatic moment a drag boat flipped and crashed on a canal during a race.

Footage shows the motorboat cutting through the waves before toppling over when the driver hit the brakes on a river in Samut Prakan province, Thailand on December 26.

The driver was flung from the boat and fell unconscious but organisers were able to quickly find and provide first aid treatment because he was wearing a life vest.

Shocked audience and drag boar racing enthusiast Warakorn Rangthongkam said: 'I watched the unconscious driver's body being retrieved from the water.

'Nobody expected that to happen during the race. I hope the driver recovers well.'

The 40-year-old driver was carried back to the land and then taken to the hospital. He had minor injuries but recovered before being discharged.