Swimmers are being urged to pull on their wet suits and take a plunge into the River Thames.
The organisers behind this year's Boulters to Bray open water swim are still searching for swimmers to take part in the event on July 6.
More than 120 people have already signed up to take on the challenge, beating last year's total of swimmers.
"We are looking for one more big push," said co-organiser and member of Maidenhead Rowing Club, Keith Dixon.
"There are quite a lot of local people doing it. A lot of people from Maidenhead Rowing Club and people who have not done it before which is what we are aiming for."
The event was staged for the first time last year following a 40-year absence.
Formerly known as the Long Swim, it dates back to the 1800s and was a highlight of the town's sporting calendar.
The 1.7 mile route sees swimmers of all ages jump into the water at 6am at Boulters Lock and battle their way through freezing waters to reach The Waterside Inn at Bray.
Keith, who will be taking part in the swim himself, said he has been surprised by the huge response to the event.
"I think the last time it was done in the Sixties about 10 people did it. It is quite incredible," he said.
"It's the exciting time now."
The event will once again be supported by The Louis Baylis (Maidenhead Advertiser) Charitable Trust and the Royal Borough.
Competitors must wear a wet suit and be capable of swimming 80 lengths of a 25m pool.
Categories include Open, Masters 49+ and Junior 15-18.
Entry is £32.
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