Marathon river swimming, also known as long-distance river swimming, involves swimming significant distances in rivers. Similar to marathon running, marathon river swimming requires endurance, stamina, and determination. A marathon swim can be any distance equal or greater than 10km. Swims take place in rivers of varying widths, depths, temperatures and current strengths – each presenting a different challenge.

Marathon river swimming events can be competitive, with participants vying for titles, records, or prizes. Or they can be recreational, with individuals or groups swimming for personal achievement or to raise awareness and funds for charitable causes. Marathon river swims take place all across the world – three of the leading swim events in Europe have come together to create the world’s first Marathon RIver Swim Series.