At 3:30pm, Thalang police were called to the scene to investigate the incident involving 21-year-old Liam Colven from Portree in Scotland.
According to staff and witnesses, the man hired an 11mm pistol and fired seven shots at the target, before requesting more bullets.
He then turned the gun on himself and fired into his head at point blank range.
Police found the body of the shirtless man lying on the floor of his booth, still holding a gun in his right hand. He was bleeding from the head.
The taxi driver, Prasert Porasaman, 43, who picked up the British tourist from Sunwing Resort and Spa in Cherng Talay, said he heard the man arguing with someone before he got into the taxi.
“I then asked him where he wanted to go and he said, ‘Take me somewhere I can shoot’ so I took him to the shooting range," said Mr Prasert.
He said that the man showed no sign of stress while he was in the taxi. The driver was waiting outside the range, when he heard the staff shouting about what had happened.
Police have checked the CCTV and have informed the victim's family and British embassy.
The footage, seen by The Phuket News, appears to show a shooting range employee loading the pistol and handing it to the tourist. He then steps back.
A split second later, apparently realising the tourist's intent, he makes a futile lunge to stop the shooting, then staggers away holding his head in horror.
The body of the victim was taken to Thalang Hospital.
If you or anyone you know is in need of mental health services, please contact the Samaritans of Thailand on their 24-hour hotline 02-713-6791 (English), 02713-6793 (Thai) or Thai Mental Health Hotline at 1323 or 1667 (Thai), or visit http://www.befrienders.org/