A 15-year-old boy is fighting for life after crashing a quad bike in a suburban street in Perth.

Witnesses say the teen wasn’t wearing a helmet when the accident happened in Swan Hill in the city’s east.

He’s in a critical condition at Royal Perth Hospital and police are investigating.

A second teenager who was also on the bike was rushed to Perth Children’s Hospital, where he is in a stable condition.

The pair were riding the blue quad bike along Morrison Road when they hit a tree just after 1pm.