Finswimming is an underwater sport consisting of four techniques involving swimming with the use of fins either on the water’s surface using a snorkel with either monofins or bifins or underwater with monofin either by holding one’s breath or using open circuit scuba diving equipment.

Events exist over distances similar to swimming competitions for both swimming pool and open water venues. Competition at world and continental level is organised by the Confédération Mondiale des Activités Subaquatiques (CMAS).

The sport’s first world championship was held in 1976. It also has been featured at the World Games as a trend sport since 1981 and was demonstrated at the 2015 European Games in June 2015.

Finswimming which is often compared to sports swimming differs from that sport in the use of masks, fins, snorkels and underwater breathing apparatus. This reflects the sport’s origins in the underwater diving techniques of snorkelling, breath-hold diving and open circuit scuba diving.

Apart from requiring the use of a mask for protection of the eyes and for the ability to see underwater, the international rules have no requirements regarding selection. Centre-mounted snorkels (also known as front snorkels) are the only type approved for use subject to meeting minimum and maximum requirements in tube length and internal diameter. Fins are also regulated by international rules.

Monofins have a maximum size which can be checked by the use of a template while bi-fins must be one of the brands certified (i.e. homologated) by CMAS.

Underwater breathing apparatus is restricted to open circuit scuba using compressed atmospheric air as the breathing gas. The use of oxygen enriched mixtures is forbidden. Cylinders are limited by maximum cylinder pressure rating of 200 bar and a minimum cylinder capacity of 0.4 litres. While there are no requirements for regulators, swimmers appear to be free to modify these to remove any unnecessary parts.

Garments such as swimsuits, swim caps and wetsuits, and the use of logos printed on these garments and the equipment is also subject to the requirements of the international rules.