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.

Other terms for inflatable boats are "inflatable dinghy", "rubber dinghy", "inflatable", "inflatable rescue boat" or "rubber duck".

Inflatable boats may have rubber floors, either plain or inflatable, or they may include steel, wood or aluminium sheets for rigidity. The tubes are made of rubberized, synthetic sheets of Hypalon or PVC to provide light-weight and secure buoyancy. The tubes are often constructed in separate sections, each with a valve to add or remove air, to reduce the effect of a puncture.

Natural rubber, also called India Rubber or caoutchouc, is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined into a usable rubber. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically. Natural rubber is used extensively in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof.

The commercial source of natural rubber latex is the Pará rubber tree (Hevea brasiliensis), a member of the spurge family, Euphorbiaceae. This species is widely used because it responds to wounding by producing more latex.

Other plants containing latex include gutta-percha (Palaquium gutta), rubber fig (Ficus elastica), Panama rubber tree (Castilla elastica), spurges (Euphorbia spp.), lettuce, common dandelion (Taraxacum officinale), Russian dandelion (Taraxacum kok-saghyz), Scorzonera (tau-saghyz), and guayule (Parthenium argentatum). Although these have not been major sources of rubber, Germany attempted to use some of these during World War II when it was cut off from rubber supplies^{[citation needed]}. These attempts were later supplanted by the development of synthetic rubbers. To distinguish the tree-obtained version of natural rubber from the synthetic version, the term gum rubber is sometimes used.

A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland (lakes) or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a vessel small enough to be carried aboard another vessel (a ship). Another less restrictive definition is a vessel that can be lifted out of the water. Strictly speaking and uniquely a submarine is a boat as defined by the Royal Navy^{[citation needed]}. Some boats too large for the naval definition include the Great Lakes freighter, riverboat, narrowboat and ferryboat. The term armed boat, used primarily by English speaking naval forces, referred to any boat carrying either a cannon or armed occupants, such as marines^{[citation needed]}.

Boats have served as short-distance transportation since early times. Circumstantial evidence, such as the early settlement of Australia over 40,000 years ago, and findings in Crete dated 130,000 years ago, suggests that boats have been used since ancient times. The earliest boats have been predicted to be logboats. The oldest boats to be found by archaeological excavation are logboats from around 7,000–10,000 years ago. The oldest recovered boat in the world is the Pesse canoe; it is a dugout or hollowed tree trunk from a Pinus sylvestris. It was constructed somewhere between 8200 and 7600 B.C. This canoe is exhibited in the Drents Museum in Assen, Netherlands; other very old dugout boats have been recovered. A 7,000 year-old seagoing boat made from reeds and tar has been found in Kuwait.