Freediving has several disciplines, each testing a different mix of depth, distance, or breath-hold time. You'll hear the abbreviations thrown around in courses and competitions — here's what they actually mean, in plain English.
Depth disciplines: CWT, CNF, FIM
- CWT (Constant Weight) — descend and ascend using fins (or a monofin), without pulling on the line or changing your weight. The most common competitive depth discipline.
- CNF (Constant Weight No Fins) — the same, but with no fins at all, using a breaststroke-style pull and kick. Widely considered the purest and most demanding discipline.
- FIM (Free Immersion) — no fins; you pull yourself down and back up along the line by hand. Great for learning equalization and relaxation, and a staple of early training.
Pool disciplines: STA, DYN, DNF
- STA (Static Apnea) — holding your breath while floating face-down, motionless. A pure breath-hold-time discipline.
- DYN (Dynamic With Fins) — swimming for maximum horizontal distance in a pool using fins or a monofin.
- DNF (Dynamic No Fins) — the same, without fins.
Quick glossary
- Duck dive — the technique used to start a descent from the surface.
- Equalization — relieving ear/sinus pressure as you descend (see essential skills).
- Mouthfill — an advanced equalization technique for deep dives.
- Mammalian dive reflex (MDR) — the body's natural adaptations to immersion (slower heart rate, blood shift) that make breath-hold diving possible.
- Residual volume — the air left in your lungs after a full exhale.
Want to train any of these? Find a freediving school in Anilao, or start with Freediving Course Levels Explained.