SUP Fin Size, Shape, and Position Explained

In Equipment, Fresh Content, General, Spotlight by Daniel

Share this Post

Let us talk about a very underrated piece of SUP equipment...

SUP Fins.

First of all, why are they underrated?

Most people paddle with a standard 8'' fin with a regular curved shape suitable for both long distance paddling and SUP surfing.

If you happen to be one of those people - great!

But most paddlers, especially new paddlers, do not realize that a different fin size, shape and position on your board can actually affect your paddling and how you feel on the water.

Since there is a wide variety of fins on the market, we want to make this breakdown as simple as possible and not focus on specific fin manufacturers, but rather general characteristics that you can consider when making your next purchase.

Let us start with the type of fin boxes for paddleboards.

SUP Fin Box

A fin box is where the fin slides into the bottom of the board.

There are Universal Fin Boxes or US Fin Boxes, FCS Fin Boxes and Futures Fin Boxes.

Most SUP boards come standard with universal fin boxes, which means aftermarket fins will work with most boards.

Surfboards and some SUP surfboards come with FCS and Futures fin boxes.

Always check with your SUP supplier before purchasing a board so you know what type of fins will fit your board.

This information is very useful if you want to buy an aftermarket fin or borrow one from a friend.


The average fin measures approximately 8".

But the length can vary from 4.5" up to 10" +.

The longer the fin and the deeper it extends into the water, the better the tracking for the paddler.

The shorter the fin, the worse the tracking, but the better the maneuverability.

The right choice of length depends on the environment you are paddling in and the type of paddling you are doing.


SUP Fin Touring/Racing

Racing fins usually have a larger overall surface area.

They tend to have a blocky design, as opposed to curved fins.

They also have a wider base and are usually longer and protrude deeper into the water.

They are shaped to provide better tracking (the ability to paddle straight for longer periods of time) and stability in the water.

However, with more stability and tracking, it is also harder to turn the board.

The wider base and larger surface area means that you will have more drag from side to side when pivoting.

Standard SUP Fin/Surf Style

Most paddleboards come standard with an 8-inch black plastic fin. And this is an industry standard for a reason.

This shape provides a near perfect balance of stability, glide and maneuverability.

These fins are still relatively wide at the base, which makes them good but not great for tracking, and the smaller surface area of the fin itself makes turning a breeze.

Their weaknesses are when paddling long distances and in choppy water.

Without the extra length, they are not as true to track as a racing fin, and with the lower surface area, they are prone to instability, especially when tipping sideways in windy conditions.

River SUP fins

If you plan on paddling rivers, you should invest in a river fin first.

River fins are made of flexible material and are much smaller in length - about 4.5" as opposed to 8"+.

This is due to the obstacles that are common in rivers.

You do not want to be paddling at your leisure and suddenly hit a rock or tree stump.

This will cause you to be thrown forward, lose your balance and possibly fall into the water!

The flexible materials are important for the same reason - if you bump into something, the fin will flex instead of breaking!

Position of the SUP fin

One aspect that is often overlooked is the position of the fin.

If you position your fin forward (or more towards the nose), you can turn more easily.

If you put the fin backwards, your board will be stiffer and you will be able to ride straight for longer, but it will be difficult to turn left or right.

Both positions can be used for your paddling style, but if you keep the fin right on the centerline, you'll be good to go in most cases!


Despite all this extra information about fins, you will be fine with a standard 8 inch fin suitable for apartment water surfing and SUP!

But for those who want to use their skills in a different environment or activity, make sure you have the right gear before you go.

Before you go...

Let us ask you a couple of questions...

Do you struggle with your balance on the water?

Do you often fall in?

Or if you are new to the sport - is it the one thing that is keeping you from going consistently or even at all?

There is help!

The best thing to do, of course, is to keep going. Practice is really the only way to quickly improve.

But for those visual learners out there...

Check out this short video from Robert Stehlik where he covers practical tips that you can use to improve balance...


If you have any questions or comments about our SUP fin breakdown, or maybe you'd like us to cover a certain topic or answer a question, feel free to contact us today!

Our inbox is always open and we are beyond excited to hear from each and every one of you.

-The Perfect Paddles Team

P.S. Interested in becoming a member? You should be! Join today and experience these benefits:

Discounts on trips around the world
Discounts on local paddling activities in your hometown
Discounts on the best SUP gear on the market
A community of paddlers eager to connect and have fun

Join today!

About the Author


Daniel is a travelling author with a passion for exploring new waterways and sharing his experiences with the world.

Share this Post