A dive boat is a boat that scuba divers use to reach a diving site which they could not reach by swimming from land.

Many types of boat can be used as dive boats. Some notable types of dive boat are:

The rigid-hulled inflatable boat

The day boat

The liveaboard

Rigid-hulled inflatable boat (RIB)

Divers only spend a few hours at a time on these fast but exposed boats. The boat being small and easily transported on roads is suitable for amateur use. These boats should carry basic safety equipment such as marine VHF radio and oxygen first aid.

The divers enter the water by rolling backwards overside, and return to the boat by climbing back in over the soft rounded tubes after removing the heavy parts of their heavy diving equipment and handing it up. An advantage of this type of boat compared with similar-sized rigid boats is that the inflated tubes make the boat very stable during the entry and exit of the divers.

Day boat

These boats are made of rigid materials - often, fiber glass. Day boats are quite large: typically, between 60 to 90 feet (27 m) in length. Many day boats are used for scuba-divers, but may also be used for any other marine enthusiasts. In general, divers or passengers will spend only the daylight hours on a day boat, and do not usually sleep in them overnight. (They will usually only sleep overnight if they are on a "live-aboard", which is a slightly different sort of boat). Generally a professional crew navigates and operates the boat. The boat provides shelter from the weather and is likely to have various facilities and area's for the passengers, such as: a toilet (called the "head") and a small kitchen (called a "galley"), which is often manned by a cook who cooks lunch for all on the boat. Day-boats usually also have a lounge (called a "saloon", where divers can relax on upholstered benches), and one or more dining tables. Many day boats also have an uncovered sun-deck outside, as well as a shaded area, for divers wishing to be out in the open air. The boat will usually have a diving air compressor, oxygen first aid, a VHF radio, a GPS and possibly gas blending facilities. In the case of divers, a day boat would be used to ferry divers to multiple dive-sites (typically between 1 and 3 sites) during the same day.

The divers enter the water by stepping off a platform and return to the boat using a ladder or a lift. Or they may transfer to and from a RIB ("Zodiac"(tm) or "rubber-duck" type inflatable boat).

Liveaboard

With these commercial boats, the divers live and sleep on the boat and dive from the boat for a few days to several weeks. A crew navigates and operates the boat. In addition to the usual domestic facilities expected by hotel guests, the boat will have a diving air compressor, oxygen first aid and possibly gas blending facilities and even a recompression chamber in some cases.

The divers enter the water by stepping off a platform and return to the boat using a ladder or a lift. Or they may transfer to and from a RIB which is carried and launched by the liveaboard.