A paddle boarder faced man-eating crocodiles during his quest to travel from source to sea along the longest river in Sri Lanka.
Kev Brady from Gloucester said he was terrified as he paddled more than 200 miles (320 km) along the Mahaweli.
He now aims to paddle the 800 miles (1,300 km) around the coast of the island of Sri Lanka.
His previous feats include canoeing along the Mississippi and swimming the length of the River Severn.
Mr Brady said he had suffered minor scratches and scrapes during the journey, but the most "frightening" thing was having to paddle past the crocodiles.
"I was on my own and standing [on the paddle board] only 2in or 3in above the water.
"I saw a two-foot long head pop up only 5m away from me.
"These are saltwater crocodiles that can grow up to 6m long and are considered man eaters.
"I was terrified."
Mr Brady said he felt relieved to have finished the river challenge.
"I was anxious and afraid most of the day and night, in between appreciating how beautiful and amazing it was.
"So there was a lot of relief when I finished - relief I've still got both arms and both legs."