A personal submarine is a submarine, usually privately funded and constructed, which is usually primarily intended for recreational use.[1]
Some are also used for scientific[1] or military[2] purposes.
Other uses include tourism, filming, water sporting, rescuing and spying. Some are as long as 285 metres (935 ft) with capacity to stay underwater for several weeks (e.g. Migaloo submarine yacht). Those personal submarines which are available for sale cost from US$16,000 to 2+ Billion USD. A wide range of them is available from 1-person to 34+ occupants, some can go just 12 meters underwater and some can even reach to Mariana Trench.[citation needed]
Such submarines can be designed from scratch by the builder or built to available plans.[citation needed]