The water between Falmouth and St Mawes will be teaming with swimmers on Sunday as the RNLI’s annual Castle to Castle swim takes place.
Four hundred people have signed up to take part in the swim and it is hoped that more than £25,000 will be raised for the RNLI.
The one-mile swim will start at Pendennis Point at 1.30pm and finish at the beach below St Mawes Castle.
Swimmers are guided across the river through a swim zone manned by RNLI lifeguards, while traffic movements in the river are restricted.
Both Falmouth lifeboats and a number of safety and support boats will also be afloat to assist in the event.
All competitors will receive a t-shirt on completion and there will be refreshments and a barbecue to greet them at the finish.
Last year’s swim was won by Haddon Page from Redruth, who completed the course in 22 minutes and nine seconds, just 42 seconds off the record.
The event is now in its sixth year and has raised tens of thousands of pounds for the RNLI in Cornwall and Devon.
This year there is a special prize for the most sponsorship money raised.
Donated by one of the event sponsors, the winner will receive a seven night stay for one at Tri-Topia in France.