The terms “floatplane” and “seaplane” are used interchangeably in some countries, but technically have different meanings.
Both a floatplane and a seaplane can take-off from, and land on, water such as oceans, seas, rivers, and gulfs. Both can transport people or supplies. A floatplane is technically a type of seaplane.
Flying Boat Seaplane
An often referred to type of seaplane is a "flying boat" which is built around a single hull which serves as the plane’s floating body/fuselage. A flying boat takes off from and lands on its belly. The term flying boat is less common as of late but is still referenced in official documentation and definitions. Often when people say seaplane, they mean flying boat.
On the other hand, a floatplane is also referred to as a "pontoon plane." Instead of a hull that can land on water, a floatplane has floats or pontoons which serve as the surfaces to land on and take off from, as is the case for the Viking Twin Otter when it has float landing gear in place. The hull/body/fuselage of a floatplane is not intended to touch the water.
Viking Twin Otters are amphibious aircraft that can take-off and land both on conventional runways, water and even on skis for snow and ice. A true seaplane can only take off and land on water.
>> Looking to learn more about landing options? Spec Your Aircraft online to see all the configurations available in Viking’s Twin Otter.