Police said around 30 European and Chinese tourists were on the boat which left Chalong at around 9am for Racha Yai on a one day snorkelling trip.
At around 11.30am, when the party had arrived at Racha, a man from another boat spotted Miss Ting floating facedown in the water, far from the other tourists. She was unconscious and taken to shore.
A nurse at the Racha hotel offered help but Miss Ting died. Her body was taken to Vachira Hospital.