Swim fins — also called flippers — are made up of a foot pocket and a wide, flat blade extending from the toes. They are made of plastic, rubber, or composite materials like fiberglass and carbon fiber. A strap usually goes around the heel to secure the foot to the fin while underwater.
Kinds of Swim Fins include the following:
Paddle fins (Paddle flippers)
Paddle fins have simple blades that serve as extensions of the feet to add underwater thrust. They are the most basic type of swim fin and are called jetfins commonly used for recreational water sports. Some types, called , have water vents that cause water to jet backwards at each kick. This results in higher speed with less paddling. Some also have grooves and channels that allow smoother water flow and more powerful kicks. They generally have low kick efficiency, but are said to be the most versatile fins.
Split fins (Split flippers)
Swim fins have slits running along each blade, dividing them into two smaller fins. The slit allows water to be scooped or suctioned backwards by each stroke, propelling the swimmer at a much higher speed. They offer the longest distance per stroke, but are hard to maneuver. This makes them difficult for performing frog kicks and other moves that require direction control.
Force fins (Force flippers)
Force fins have wider blades that are upturned for a scooping effect similar to split fins. They are usually made of polyurethane. They offer high acceleration and distance per kick, making them ideal for racing and competitive swimming. They are usually hard to maneuver, as the blade shape directs the water at a fixed direction. They are usually difficult to use with neoprene boots or other buoyant devices.
Freediving fins (Freediving flippers)
Freediving fins have extremely long blades designed for low-energy kicking. They are designed for minimum oxygen and energy consumption. They can also achieve high speed and acceleration, although they are still slower than split fins.
Choosing Swim Fins (Buying Tips)
Foot pockets: You can choose between a full-foot swim fin or an open one that you can adjust with the heel strap. Choose a full-foot fin for a more natural feel, and an open one for less weight and lighter movement. Also make sure that the inside if soft and comfortable.
Flexibility: Choose a swim fin with a flexible blade if you are a beginner, moving up to stiffer fins as you get better. Stiff fins feel heavier and require stronger kicks to achieve high speeds. Make sure it bends equally in both directions, which will allow you to use different swim styles.