Thomas Marshall, a student at The Samworth Church Academy, Mansfield, is doing a sponsored swim of 80 lengths at Water Meadows, Mansfield, to raise money for Children In Need.
He plans to swim for 90 minutes on 17th November and aims raise £1,000.
Thomas has previously swum to raise money for Help For Heroes, collecting £258 after swimming 60 lengths in under an hour.
Anyone who wants to make a donation can go to