Patong Police received a report of the fire at Karnda Massage on Phra Metta Rd at about 7:50am, shortly after the incident occurred at around 7:40am.
Police patrol officers, investigators and the duty investigating officer responded to the scene, where they found the five-storey building housing a massage business and residential accommodation.
Firefighters brought the blaze under control before it could spread further.
No injuries were reported among residents or occupants of the building, police confirmed.
Initial inspections found only minor property damage, mainly affecting chairs inside the premises.
According to residents, strong winds and heavy rain were affecting the area before the incident. Witnesses reported hearing an explosion from an electrical transformer inside the building before smoke began filling the structure and a fire subsequently broke out.
The exact cause of the fire has yet to be determined.
Patong Police have notified forensic officers to examine the scene and conduct a detailed investigation into the cause of the blaze.
The incident was reported to Phuket Provincial Police by Patong Police Station under the supervision of Patong Police Superintendent Col Korakrit Khanthakrue.