The explosions happened ahead of a public holiday on August 12 to mark the birthday of Queen Sirikit. Hua Hin is a popular upscale Thai resort south of Bangkok and many people will have gone there for the holiday weekend.
The second bomb exploded near a bar at about 10:20 p.m. (1320 GMT), killing a Thai woman and injuring eight foreigners and one other Thai person, local deputy police chief Samer Yousamran said.
The injured are being treated at a local hospital, he said.
The first bomb went off about twenty minutes earlier about 50 meters (yards) away from the second bomb, he said. Nobody was injured in the first explosion.
Police are investigating and as yet do not know the motive or the identity of the bombers, he said.
In a separate incident earlier on August 11, a bomb exploded at a market in the southern Trang province in Thailand, injuring six people, police said.
Police believe that explosion was related to a local dispute.