2. Waikiki Roughwater Swim

The Buzz -- Seasoned swimmers and those on a personal mission take to the beautiful waters off Waikiki in late summer for this 2.384-mile course. The open-ocean race begins at Sans Souci Beach and finishes at Duke Kahanamoku Beach, and competitors are sent out in groups to keep the field manageable. One of the islands' two ocean swims (along with the Maui Channel Relay), the Waikiki Roughwater is also notable for having been the model for the swimming portion of the original Ironman Triathlon.