A woman who went missing on Monday while swimming at a beach in Shizuoka Prefecture was found alive 36 hours later off the coast of Chiba Prefecture on Wednesday morning, according to the Japan Coast Guard.

The woman, who is a Chinese national in her 20s, was dehydrated but conscious and did not require hospitalization.

The woman had brought an inner tube and was swimming with a friend at Shirahama Ohama beach in the city of Shimoda, Shizuoka Prefecture, at around 7:30 p.m. on Monday. She was reported missing around 30 minutes later.

She had been drifting in the sea with her inner tube for about 36 hours until she was found around 80 kilometers away, the Yokosuka Coast Guard Office said.

According to the coast guard, a cargo ship sailing off the coast of Nojimazaki on the Boso Peninsula in Chiba Prefecture found the woman shortly before 8:00 a.m. on Wednesday.

In a video provided by the Yokosuka Coast Guard Office, the woman could be seen standing on the ship wrapped up in a blue blanket before being pulled up by a helicopter operating out of Haneda Air Base.

She was then handed over to an emergency medical service team to be transported to a hospital in Yokohama.

In an interview, she told the coast guard that she was swept out to sea and was unable to return to the beach while swimming at Shirahama Ohama beach.

At the time of the rescue, the weather was sunny, with air temperatures at 28.5 degrees Celsius and water temperatures at 24.1 C.

The crew members who helped her onto the ship reportedly mistook her as a crew member who had fallen into the ocean from another ship, saying that when they tried to rescue her she was too weak to climb up the ladder.