Kathu police told The Phuket News that bus driver Pravet Wongthai, 51, was carrying 20 international tourist from Karon to a hotel in Patong about 6pm in heavy traffic.
He discovered his brakes were not working as he was driving near the Simon Cabaret.
Mr Wongthai told police he was not driving fast and had tried to zigzag past other vehicles before the collisions.
Four people suffered injuries in the accident, none seriously.
The bus company and the victims will discuss payments for damages in a meeting on January 4.