An amazing survival story comes from the southeast coastal waters of Japan where a Chinese woman survived days adrift at sea clinging to an inflatable intertube.

Reported missing last Monday by her friends, the unnamed Chinese national was swimming with friends on a beach in the city of Shimoda, Shizuoka Prefecture.

The coast guard was alerted that she was in her 20s and holding onto an inflatable recreational intertube.

The woman wasn’t located in Shizuoka, and it wasn’t until 8:00 am on Wednesday, 36 hours after going missing, that a passing cargo ship encountered her in the waters of the Boso Peninsula in Chiba Prefecture.

She had floated over 50 miles (80 kilometers) during that time, but mercifully the waters hovered around 24.1 degrees Celsius, or about 75 degrees Fahrenheit.

Being extremely large, the cargo ship hailed a passing tanker to help. Two of its crew members, believing the drifting speck of humanity in the vast empty ocean was a member of the cargo ship’s crew, jumped in to rescue her, while those remaining onboard called out for her not to give up.

Once in the water, the crew secured a rope around her waist as she was too exhausted to climb the ladder. After 36 hours and several tense minutes, the young woman and her sodden, wobbly knees were on deck.

Video released by the Japanese coast guard who eventually air-lifted the woman to a hospital, shows her standing on the tanker’s main deck wrapped in a blanket. Apart from exhaustion, the woman was unharmed and walked out of the hospital of her own initiative.

Hidetoshi Saito, a senior member of the Society of Water Rescue and Survival Research, said in a televised interview that the woman’s survival was like “a miracle.”