The Russians, a pair of husband and wife, were riding a motorbike on a coastal road towards Mui Ne beach town at around 4:30 p.m. when they reached a turn and collided heads-on with the other foreigner, whose nationality has not been confirmed.
The strong impact caused all three to fall down and severely damaged the motorbikes. The Russian man died on the spot, while his wife was severely injured. The other foreigner, a man, was also taken to hospital but succumbed to severe injuries.
Police have inspected the scene and are investigating the cause of the accident.
The coastal road connecting downtown Phan Thiet with Mui Ne, spanning 20 km, is a popular tourist site, especially to foreigners.