The OSS Dart 10K (or the Dart 10k) is organized by the Outdoor Swimming Society and is a 10 km swim down the River Dart in Devon, England. The swim is not a race, but a participation marathon swim where swimmers can swim at their own pace downstream in brackish water through the rolling hills of Devon to the small waterside village of Dittisham. In 2015, it will become a 10-mile swim.
Since 2009, it has grown from 200 swimmers to 1600 swimmers. It is a journey and one of the World's Top 100 River Swims.
The River Dart is a river in Devon, England which rises high on Dartmoor, and releases to the sea at Dartmouth.