— Chapter 01

How It Works

A monofin connects both feet together on a single rigid or semi-rigid blade, propelling the diver through the water using a full-body dolphin kick rather than alternating leg strokes. In competitive freediving, it's the primary tool for pool dynamic apnea (DYN).

Both feet slot into pockets on either side of a single blade. The diver swims with a dolphin kick — the whole body undulates in a wave from head to tail, with the monofin providing the propulsive surface.

The efficiency advantage
when the dolphin kick is correct, the monofin converts more of the body's energy into forward motion than bifins do — force is applied once per stroke cycle with both feet together
The catch
the dolphin kick requires whole-body coordination that takes months to develop — a poor dolphin kick on a monofin is less efficient than a good bifin flutter kick
— Chapter 02

When Monofins Make Sense

Pool DYN Training and Competition

This is where monofins dominate. All world records in DYN are set on monofins. Competitive pool freedivers who target DYN distances train almost exclusively on monofins once their technique is established.

Technique Development

Learning the dolphin kick on a monofin develops body position and undulation efficiency that carries over to bifin diving. Many coaches recommend monofin work specifically for divers with weak body undulation in CWT.

Not for Open Water Recreational Diving

Bifins are better. The bifin flutter kick is easier to sustain across long ascents and descents. Equalization hands (Frenzel) are easier when the kick is less demanding. Maneuvering around reef features is easier.

Not for Spearfishing

Bifins only. Lateral control and maneuverability are essential for pursuing fish.

— Chapter 03

Entry-Level Monofins Worth Considering

Option
Notes
Price
Leaderfins Monofin
Most accessible entry-level option, multiple stiffness
$80–150
Omer Stingray Monofin
Mid-range, good build quality, comfortable pockets
$180–250
Finis Competitor
Designed for swimmers, widely available
$120–180
Molchanovs Monofin
Premium, competition-grade
$400+
— Chapter 04

Learning the Dolphin Kick

The dolphin kick is a full-body movement that initiates from the core, not the ankles.

The sequence

  1. 01 —Chest leads slightly downward
  2. 02 —Hips follow, driving downward
  3. 03 —Knees bend slightly, loading the blade
  4. 04 —Ankles extend — blade snaps through its arc

Common errors

  • Kicking from the knees only — reduces power significantly
  • Rigid torso — blocks energy transfer through the body
  • Kicking too fast — wrong frequency for the blade's stiffness

Learning approach

  1. 01 —Pool drills starting at 12.5m (half a lane), full rest between sets
  2. 02 —Use a pull buoy for first sessions — isolates kick without the arm streamline variable
  3. 03 —Video feedback from a training partner accelerates technique development significantly
3–4 months
Before monofin outperforms bifin distances
Expect 6–8 weeks before the kick feels coordinated. It takes 3–4 months of consistent pool work before the monofin delivers on its efficiency promise.