The collision left five of the tourists injured, as well as the speedboat captain and his crewman.
The heavily damaged speedboat, the “Sainam”, returned to Yamu Pier in Pa Khlok, where rescue workers were waiting for them.
Acting Chief of the Phuket Marine Office Wiwat Chitchertwong explained that twin-engine Sainam departed Yamu Pier at 9am after being chartered by one of the Chinese tourists for a day trip to Phi Phi Island.
On the way back to Phuket, the Sai Nam struck an oil tanker called the Chok Kriangkrai near Koh Rang, heavily damaging the tour speedboat.
The tanker suffered minor damage under its left bow.
The accident occurred about 2:30pm, Mr Wiwat said.
The tourists were brought ashore and the injured were provided first aid before all of them, along with the Thai captain and crewman, were taken to Thalang Hospital and Mission Phuket Hospital.
Officials have confirmed that there have been no deaths from the collision, but have yet to confirm the extent of the injuries of those rushed to hospital.
The Phuket News has confirmed that among them is a 6-year-old, a 13-year-old and 16-year-old.
Mr Wiwat assured that an investigation is now underway into how the collision occurred.