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Are Paddleboard Fins Universal? Helpful SUP Fin Guide

Updated November 30th, 2023

Are paddleboard fins universal

Are paddleboard fins universal? There are many different types of paddleboard fins on the market, and it can be difficult to know which ones will fit your board. Not all fins will fit all paddleboards. In this blog post, we’ll take a look at some of the most common fin boxes, and explore whether or not you can get aftermarket fins to fit any board.

Are paddleboard fins universal?

Fins are an essential part of paddleboarding, providing the board with much-needed stability and maneuverability. Most stand up paddleboards, whether they are rigid or inflatable, have a detachable fin. However, not all fins are universal. In fact, there are several different types of fin boxes and fin systems which all have unique fins. So, before heading out to purchase a new fin, be sure to check the type of fin box on your stand up paddleboard and the fin size. Otherwise, you may end up with a fin that just doesn’t fit.

What are the most common fin boxes?

Paddleboards come with different fin setups depending on the board’s intended use. The three most common fin boxes used are the slide in fin box, the nylon Flip lock fin box, and the US fin box.

Common SUP fin types
Left to right – Slide In (left), Flip Lock (center), US Fin Box (right)

Slide In or Quick Clip Fin Box

The slide in or quick clip fin box is the easiest to use and is great for beginners or those who want to paddle in a variety of conditions. It is a simple slot fin box that the fin slides into. There is a plastic clip that slides in to secure the fin. This is a simple and cheap fin box. It is not a very stiff fin mount so it’s only found on recreational paddleboards. Some fins don’t slide in and out of their slots easily. A little sand in the slot can make a fin challenging to get on and off.

Slide in fin boxes are found on almost every cheap inflatable paddle board sold on Amazon. It’s by far the most common fin box on under $500 inflatable SUP paddleboards.

Quick clip fin and box
Quick Clip fin

Flip Lock Fin Box

The nylon Flip lock, Quick-lock, or click fin box is a bit more difficult to use but provides a more secure connection and is better for racing or surfing inch waves. This fin box has a nylon latch that is locked down after inserting the fin to hold it in place. This fin box is stiffer and more robust than the quick clip fin. It theory it works great. If the fin or fin box is a little out of tolerance the nylon latch can be difficult or impossible to latch without modifying the fin.

An unlocked fin or partially locked fin can fall out and be lost while paddling. Some new boards with this fin type such as the iRocker Ultra boards have started adding small tethers. The fin isn’t lost if the lock isn’t secure.

Common brands that use flip lock fins are iRocker, Thurso Surf, Bluefin, and Jobe.

Flip Lock fin and box
Flip lock fin

US Fin Box

The US fin box is the most difficult to use but is the strongest and most durable option, making it ideal for big wave surfing or paddling in heavy chop. This fin box has a box and slot with more structure similar to the Nylon flip lock fin box. It uses a screw attachment at the front of the fin to hold the fin securely in place. On smaller fins, the screw can be at the rear of the fin instead.

This is the most universal fin box option where you have the most aftermarket options. The fins do not have to be the same length as the fin box to work. The biggest downside to this fin box is the small screw can catch seaweed and grass which might slide past other fin boxes.

Common brands that use US Fin Box are Red Paddle Co, Starboard, NIXY, Freein, and many others.

No matter which fin setup you choose, make sure you’re familiar with how to use it before heading out on your next paddleboarding adventure!

US Fin box fin and box
US Fin box fin

Can you get aftermarket fins to fit any board?

Many people who are new to stand up paddleboarding (SUP) don’t realize that you can actually get aftermarket fins for your board. While most boards come with fins that are fine for general use, there are a variety of specialized fins that can provide different benefits. For example, racing fins can help you go faster, while touring fins can help you keep a straight line in flat water conditions.

If you’re looking to change up your SUP experience, replacing your fins is a great place to start. Just be sure to do your research and get the right size and type of fin for your particular board.

If you have a slide in fin box, there are very few aftermarket fin options. There are a few basic fin shapes available. They are direct replacements for the fin your board came with no variations in shape or size.

There is some variety of fins available to fit nylon flip lock fin boxes. iRocker sells a river fin that is shallower with more rake than the standard fin. They also sell an adapter to use a Bixby Outboard Motor with the flip lock fin box. Eisbach Riders makes a nice upgraded touring fin that works with the flip lock box.

The US Fin Box is where you find the most variety of fins. You can find flexible shallow water river fins to longer touring fins. This fin box has been in use for a long time for both surfboard fins and windsurfers so there is a lot of variety out there.

How do you know which paddle board fin will fit your stand up paddle board?

How do you know which fins will fit your paddleboard? Check which type of fin box your board has. The new fin must use the same fin box type. A US Fin Box can use fins with different sized bases. A Nylon flip lock fin must be the same size as the fin box to work. Your new fin must have the same fin box type as your paddleboard. It must be a compatible length with the fin box as well.

What are the benefits of using an aftermarket paddleboard fin?

Aftermarket fins can help you get better performance from your paddleboard, as well as improve stability and speed. Let’s take a look at a few of the more common fin types.

River Fins

Shallow water river fins are specifically designed for use in shallow rivers and streams, and can help you navigate through tight spaces without hitting bottom. They also can use more flexible materials so that you don’t damage the board scraping the fin against rocks or logs.

Badfish River Fin

Badfish River Fin product image

Touring Fins

Touring fins tend to be longer with less rake. They perform best going in a straight line on flat water with consistent water flow.

Eisbach Riders Touring Fin

Eisback Riders Touring Fin product image

Race Fins

Race fins tend to be straight with no rake. They are deeper than any other fin type. They are designed to provide directional stability with minimum drag. They are designed to be the fastest fin going in a straight line on a course.

saruSURF 9″ US Box Center Race

saruSURF Race Fin product image

Surfing Fins

Surfing fins or Dolphin fins will have more sweep and curved tips. This is so they fins don’t stall out while the board is maneuvering.

Although aftermarket fins may cost more than the standard factory-installed ones, they can make a big difference in how your paddleboard performs. If you’re looking to get the most out of your paddleboarding experience, it’s worth investing in a good set of aftermarket fins.

Santa Barbara Surfing SBS Longboard & SUP Fin

Santa Barbara Surfing Longboard Fin product image

Can I add an additional fin to my stand up paddleboard?

Some paddleboarders choose to add an additional fin to their boards. If you would like to try wingsurfing with your SUP you need to have an additional center fin in the middle of the board. An additional small fin at the front of the board can help with tracking in waves and river rapids.

While most boards come with a single fin, there are fin boxes that can be glued to the bottom of both a rigid and inflatable SUP board. That way, you can add as many fins as you like! Just be sure to choose the right size and type of fin for your needs. An extra fin might just be what you need to get the performance you want from your SUP board.

air7 Fin Box for Inflatable SUP Paddleboards

Air7 Fin Box product image

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Doug Ryan Portrait Skiing 200x200

Doug Ryan
Co-Founder & Chief Editor

I grew up back east in Pennsylvania and learned to ski on a family trip to Killington, Vermont when I was 6. I immediately fell in love with the mountains and outdoors and have been skiing across the US and Canada ever since. I went to school for Mechanical Engineering, and have a Master’s Degree in Material Science and Reliability.

I am a total gear nerd and love learning how things work and thinking about how they could be improved. Nothing excites me more than trying out new gear. I’d rather spend 3 hours taking my bike apart and learning how to change something than go to a bike shop. These days I reside in Michigan by the Great Lakes and go skiing, biking, and boating as much as possible.