An inflatable is an object that can be inflated with a gas, usually with air, but hydrogen, helium, and nitrogen are also used. One of several advantages of an inflatable is that it can be stored in a small space when not inflated, since inflatables depend on the presence of a gas to maintain their size and shape. Function fulfillment per mass used compared with non-inflatable strategies is a key advantage. Stadium cushions, impact guards, vehicle wheel inner tubes, emergency air bags, and inflatable space habitats employ the inflatable principle. Inflation occurs through several strategies: pumps, ram-air, blowing, and suction.

Although the term inflatable can refer to any type of inflatable object, the term is often used in boating to specifically refer to inflatable boats.

A distinction is made between high-pressure and low-pressure inflatables. In a high-pressure inflatable, structural limbs like pillars and arches are built out of a tough, flexible material and then inflated at a relatively high pressure. These limbs hold up passive membranes. The space where the visitors or inhabitants stay is under normal atmospheric pressure. For example, airplane emergency rafts are high-pressure inflatable structures. Low-pressure inflatables, on the other hand, are slightly pressurized environments completely held up by internal pressure. In other words, the visitors or inhabitants experience a slightly higher than normal pressure. Low-pressure inflatables are usually built of lighter materials. Both types of inflatables (the low-pressure type more so) are somewhat susceptible to high winds.

A balloon is an inflatable flexible filled with air and also gas, such as helium, hydrogen, nitrous oxide or oxygen. Modern balloons can be made from materials such as latex rubber, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders ^{[citation needed]}. Latex rubber balloons may be used as inexpensive children's toys or decorations, while others are used for practical purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and low cost, have led to a wide range of applications. The inventor of the natural latex rubber balloon, (the most common balloon) was Michael Faraday in 1824, via experiments with air and various gases.

Inflatable castles and similar structures are temporary inflatable buildings and structures that are rented for functions, school and church festivals and village fetes and used for recreational purposes, mainly by children. The growth in popularity of moonwalks has led to an inflatable rental industry which includes inflatable slides, obstacle courses, games, and more. Inflatables are ideal for portable amusements because they are easy to transport and store.

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 are often flexible. On boats longer than 3 metres or 10 feet, 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 easily be 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", or "inflatable rescue boat".