Here is a tricycle that lets you get a fun workout over any lake or open water. The Tropical Resort Aqua Tricycle has a rugged construction with three buoyant polyethylene wheels supported by a stainless steel and extruded aluminum frame. One or two people can pedal to propel the tricycle forward.
The wheels and the polyethylene seat are sun, rain, salt, and abrasion-resistant. Supports up to 450lbs.