Fins have undergone many innovations. Early fins were made of stiff rubber, while most modern fins are extremely flexible.

Although fin design varies by manufacturer, there are some common features and components that most have in common.

Many fins include channels that direct water along the length of the fin. Channels can be as simple as a vein that protrudes from the fin surface, or as sophisticated as a flexible rubber groove that also allows the fin to cup the water over the blade.