The Royal Thai Navy Third Area Command was alerted to the boat fire at 6:30pm.
Although the Third Area Command (RTN 3AC) main headquarters are at Cape Panwa in Phuket, the 3AC operates a Naval base in Thap Lamu.
The HTMS Lipe was dispatched to the scene, in the Thap Lamu Channel, and successfully extinguished the blaze, reported the 3AC.
The extent of the damage has yet to be reported, though it is expected to be considerable.
No people were injured by the fire or by the efforts to douse the blaze, the 3AC confirmed.
The cause of the fire is still under investigation, the 3AC noted in their report.
The liveaboard tour boat, the ‘Sea World 1’, is well known among dive tourists heading out on tours to the Similan Islands and further north.
The boat, 22 metres in length, featured an upper deck with open-air saloon and dining area, plus a large sun deck.
The boat could carry 18 guests maximum and featured nine air-conditioned cabins, with standard twin/double cabins with shared bathrooms or ensuite VIP doubles.
The Sea World 1 had received many positive comments in reviews online.