an organized event in which people swim a long distance in order to raise money for charity (= organizations that give money, food, or help free to those who are in need, or that provide money for causes such as medical research)

The competition pool hosts swimathons and galas throughout the year. 该比赛游泳池全年都会举办游泳马拉松比赛和晚会。

A swimathon organized by Darlington Rotary Club raised £6,500. 达林顿扶轮社组织的游泳马拉松比赛筹集了6,500英镑。