Island loop route
noun - An island loop route, as defined by the Marathon Swimmers Federation, begins by entering the water from one land mass, swimming out and around an island, and then returning to the starting point.
According to MSF, island loop routes have three key features:
1. They are nonstop (unlike multi-way swims which finish each leg by exiting the water).
2. They use only natural land features as the route markers (unlike buoy courses).
3. They can be considered "current neutral" since any potentially helpful current would likely be offset by swimming against in the opposite direction.