One tank,
breathing the sea
Breathing underwater, on your back.
SCUBA stands for ‘Self-Contained Underwater Breathing Apparatus.’ Instead of relying on a surface hose, you breathe underwater from compressed gas in a back-mounted tank, delivered by a regulator matched to ambient pressure. This overview covers only the definition, history and broad categories.
Self-Contained Underwater Breathing Apparatus
It is both the method and the equipment by which a diver breathes underwater from compressed gas in a back-mounted tank, delivered by a regulator matched to ambient pressure rather than a surface hose. The acronym ‘SCUBA’ is generally credited to Christian J. Lambertsen, a U.S. specialist in diving and environmental medicine, who is said to have proposed it in the early 1950s.
- Sources differ on the year the term ‘SCUBA’ was coined — 1952 vs 1954 — so we avoid stating it definitively.
The invention that popularized modern scuba
Jacques-Yves Cousteau and engineer Émile Gagnan co-developed it in 1942–43, with the patent and test dives carried out in 1943. The key breakthrough was the demand regulator, which supplies air only on inhalation, enabling longer and safer autonomous dives.
How the breathing gas is handled
Scuba splits into two types by how the breathing gas is handled.
Exhaled breath is released straight into the water as bubbles. Simple and inexpensive — the standard for recreational diving. Almost all entry-level gear is open circuit.
Recirculates exhaled breath (a scrubber removes CO₂, then oxygen is topped up). Long, bubble-free dives, but complex and expensive, requiring dedicated training and maintenance.
You keep breathing through your gear
The essential difference with scuba is that you keep breathing underwater through your gear. Everything else is based on breath-holding (apnea) — snorkeling is surface observation (within ≈5m), while skin diving and freediving are single-breath descents.
- Sources differ on the year the term ‘SCUBA’ was coined (1952 vs 1954) — not stated definitively.
- Earlier prior art to the Aqua-Lung exists — it was the ‘decisive invention that popularized’ scuba, not the ‘first.’
Learn to breathe,
and the sea opens up
Learn to breathe, dive in.