https://www.marathonswims.com/
Marathon Swims, London Aquatics Centre
Marathon Swims - The ultimate swimming challenge. Swimming now has its own marathon. Take on the Marathon 10k, Half Marathon 5k or 1k Challenge
marathon swimslondonaquaticscentre
https://www.tahoeopenwater.org/
Lake Tahoe Open Water Swimming Association – Solo and Relay Marathon Swims
Solo and Relay Marathon Swims
open water swimminglake tahoe