A waterbike is roughly what it sounds like: a bike frame on floats or hydrofoils that you pedal across the water. On foils, once you get up to speed the whole thing lifts clear of the surface and you glide along almost silently, which is a genuinely odd and lovely feeling.
The first few goes involve some wobbling and the odd splash while you find the balance point. An instructor sets you up and talks you through it, and most people are riding within a session. Buoyancy aid and the bike are provided.
The operators on adventuro run supervised waterbike sessions on calm water. Be ready to fall in once or twice on the way to that magic gliding moment.
