Charity swimmers swept out to sea during Joss Bay race
Up to 80 people were rescued after they were swept out to sea during a charity swim to raise cash for the RNLI.
All the swimmers had been taking part in a 3.8km charity race round Joss Bay, Broadstairs, Kent on Sunday.
Dover Coastguards said they were called to the bay at about 10:30 BST and spent about two hours searching for all the missing participants.
Watch manager Gordon Wise said: "It could have potentially been a very serious event, a very serious problem."
He added: "When we got down there we found that there was a number of swimmers that had gone out, I understand the numbers are in the high upper tens.
"In the end through a search between two inshore lifeboats, rescue boats, and some paddle boarders which were part of the event, all people were brought ashore and accounted for.
"It was a long job. It went on for nearly two hours.
"There are some bad tides that run along there, rip tiding. Especially at the moment we are coming up to some of the highest tides of the year."
One swimmer, Mike Jennings from Gravesend, said just three people managed to finish the race.
He added: "I managed to struggle round two [laps]. The latter part of the second lap I did, it took me 10 minutes to swim 50 yards to get past the marker buoy.
"After that I felt the current pushing me rapidly back up the Thames [Estuary] . So I headed for the lighthouse on top of the cliffs there.
"I don't suppose anybody out there has got more experience than me and I literally swam for that lighthouse and just about made it back to where we started.
"Other people behind me were being swept up the Thames."
Mr Jennings added: "I didn't realise the seriousness of it until I got back to shore.
"They were still bringing them back at least an hour after I'd finished.
"I did two of the three laps and I realised that there was no way I going back out there for that third lap, just un-swimmable in one direction."
The race had been organised by event and coaching company VoTwo to raise funds for the RNLI.