The man, named by police as 39-year-old Mikhail Korneev, was on the beach drinking with friends and last seen running into the water, reported Lt Col Somnuek Damkaew of the Kamala Police.
Police were alerted to the situation at about midnight, he added.
Earlier yesterday evening, Mr Korneev arrived in a taxi with friends at the hotel nearby where he checked out two days ago, Col Somnuek explained.
“His friends told us that Mr Korneev was drunk so they paid the taxi fare for him,” he said.
“They said they were drinking some more at the beach, when Mr Korneev suddenly ran into the water and disappeared,” he said.
“Police and rescue workers searched for him along the beach last night, but they did not find him, so today we are out looking for him again,” Col Somneuk noted.
“So far there has been no sign of him,” he said.