A TELEVISION presenter and two members of Leander Club took part in the 11th annual Henley Classic swim early on Sunday.
They were among 85 swimmers from around the world who joined the 2.1km race along the royal regatta course, beginning by Temple Island at 4.30am.
The competitors were split into categories depending on their ability.
The course was marked with a giant laser beam which shone down the river to show swimmers the route.
Click here to see more photographs of those who took part.
Ski Sunday presenter and former Olympic skier Graham Bell took part in the event for a fifth time. He was in the sporting category for which official times arent recorded.
Bell, who lives in Henley, said: It was an excellent morning, very well organised with beautiful conditions.
I didnt do too badly Ive been doing quite a bit of swimming recently and Im reasonably fit.
Leander rower Rachel Gamble-Flint took part for the second year and came third in the open womens category with a time of 35 minutes and 22 seconds.
Miss Gamble-Flint, 22, who lives in Gravel Hill, decided to take part after having to pull out of this years Henley Royal Regatta with a back injury. She said: My injury means Ive not been able to do any rowing for a few weeks so Ive been training in the pool at Gillotts.
Henley Classic organiser Jeremy Laming was often there at the same time so he sort of became my training partner and encouraged me to take part.
I really enjoyed it when I was out there and it went quite well considering my injury. Like rowing races, you get carried along with the competition. The event is well organised and the atmosphere was really positive. Leander and GB cox Zoe de Toledo took part for the first time this year in the sporting category and raised more than £1,000 for the MS Trust.
Miss de Toledo, 26, of Crisp Road, Henley, said: I was in the less competitive division for people who didnt want to get kicked in the face at the start line!
Our category was right at the end and I really enjoyed the swim, more than I thought I was going to. The start was quite frantic and I hadnt appreciated how choppy the water would be but once I got away and found a bit of space I really got into it and relaxed.
I entered the swim on a whim really and the day after I woke up thinking what am I doing? However, I did a bit of training in open water and got used to it so I really went for it on the day.
Reigning champion Alex Studzinski, a Frankfurt police officer, retained his title as he finished first overall with a time of 24 minutes and 45 seconds.
Fellow German Beatrix Eisel, who finished second in the elite womens contest last year, went one better as she won the womens title this year in a time of 27 minutes and 48 seconds.
Mr Laming, who founded the swim in 2004 with Tom Kean, said: It cant be understated how much work goes into laying on an event such as this and the Henley Classic would never happen if it wasnt for an army of volunteers.
The winners trophies were presented by Mr Laming at the River and Rowing Museum.
This year, there was also an open-water varsity match between Oxford and Cambridge universities, which the former won.
The laser was provided by A10 networks and the official timekeeper was luxury watchmaker Bremont, of Marlow Road, Henley.
The next swim event will be the Henley Mile on July 13. For more information, visit www.henleyswim.com