And we want to help you get into the spirit of the occasion with a look back at some archive swimming scenes from across Wearside and County Durham.
More than 450 pools across the UK are hosting Swimathon sessions until Sunday, including a number in the Sunderland area.
Find out more at https://www.swimathon.org
And in the meantime, let’s float back in time to these scenes from Farringdon, Hetton, Hendon, Sunderland Aquatic Centre and Peterlee.
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