A woman who was swept out to see while swimming at a beach in Japan has been rescued about 80km (50 miles) off the coast, 36 hours after she went missing, officials have said. The 21-year-old Chinese national, buoyed by a rubber ring, had been swimming at Shirahama Ohama beach at about 7.30pm on Monday with a friend, the coast guard said on Thursday. Authorities launched a search and rescue operation after her friend raised the alarm at the beach in the central Shizuoka region that same evening. “It was around 7.55pm on July 8 when we received the information after the woman’s friend reported to a nearby convenience store that she was missing,” a local Japan coast guard official said. The woman, who was not named, told rescuers that she was swept out to sea and could not return to the beach as she was swimming with a rubber ring. She was finally spotted floating off the southern tip of Chiba’s Boso peninsula by a cargo ship at 7.48am on Wednesday, the official said. Two crew members of a smaller nearby tanker were contacted by radio and jumped into the sea to rescue her. “There are 80km in a straight line [between the beach and rescue spot] … but it is assumed she drifted for an even greater distance,” the official said. The woman was taken to hospital after the rescue but did not need to be admitted as she was clear-headed and her dehydration was not life-threatening.