Two people, one a seven-year-old boy, were killed when their hired jet ski collided with another jet ski in the sea off Pattaya beach early on Monday night.

Police were called to the scene, a beach near Pattaya's Walking Street, about 7pm. Witnesses said two jet skis had collided. The driver of one machine and a boy riding pillion were thrown into the water by the impact.

The boy, 7, was wearing a life jacket and was helped out of the water by jet ski operators. He was seriously injured, including a broken jaw, and was rushed to a hospital, where he was later pronounced dead.

The jet ski driver, 35, was found drowned, located by rescuers after a 30-minute search.

The witnesses said the driver of the other jet ski was of Indian appearance. He had walked away from the scene after the collision, and disappeared.

Police were examining security camera recordings from the scene to establish the cause of the accident and locate the other driver.