An inflatable boat is a lightweight boat constructed with its sides and bow made of flexible tubes containing pressurised gas. For smaller boats, the floor and hull beneath it is often flexible. On boats longer than 3 metres (9.8 ft), the floor often consists of three to five rigid plywood or aluminium sheets fixed between the tubes but not joined rigidly together. Often the transom is rigid, providing a location and structure for mounting an outboard motor.
Some inflatable boats have been designed to be disassembled and packed into a small volume, so they can be easily stored and transported to water when needed. Here the boat when inflated is kept rigid crossways by a foldable removable thwart. This feature allows such boats to be used as liferafts for larger boats or aircraft, and for travel or recreational purposes.