Surf Fins Buying Guide

The world of surf fins is one that is often overlooked when buying your first surfboard set-up. That’s fair enough though – when you’re focus is on standing up on a wave for the first time, your mind is probably elsewhere, so naturally, surfboard fins take a bit of a backseat. As your surfing progresses and the horizons of more specific (and generally shorter) boards opens-up, fins should become an intrinsic part of your gear selection too.

What surf fins do I need?

Fins will influence how your board feels. They can either compliment a board or it can work against it and turn it into a pig. Switching your fins over can also completely change the feel. If your relationship with your board is in a rut, spice things up with the addition of some sexy new fins.

There’s a lot to think about when buying fins. The main thing that controls your choice is what kind of fin boxes and box configuration your board has – we’ll talk about all of that shortly. Your selection will also be controlled by your weight, ability and budget. Conditions impact how fins perform too, so with that in mind, having an array of fins at your disposal is handy.

If you’re oblivious to surf fin terminology like flex, fin box, configuration, foil, sweep, rake, drive and hold – fear not. Read through our surf fins buying guide and let us help you get the right fins for you.

We'll be looking at all of this:

  • How surf fins work
  • Surf fin brands
  • Surf fin configuration
  • Fin terminology
  • Templates and surf fin measurements

To guide you through:

  1. Identifying which brand you need
  2. Finding the fin set-up for you and your board
  3. Deciding how you want your board to feel

Sounds simple, right? Eventually we hope it will be but until then, it's time to go to school.

How do surf fins work?

Well, read further on and you’ll learn that all fins are different, and no two perform in the same way from surfer to surfer. We’re not going to go too deep into the world of hydrodynamics for now – so simply put, a fin’s positioning, shape and the material it’s made from respond differently as they move through the water, this in turn creates various forces that affect the way your surfboard responds. When reading through our wonderfully-detailed product descriptions, you’ll tend to notice four forces mentioned – hold, drive, drag, and lift. We’ll talk about these in detail later and how they can drastically affect speed, control and how you turn your board in different conditions.

Fin Box Types and Fin Brands

The brand of fins available to you are limited by the fin box your surfboard has been shaped with. Flip your board over, what do you see?

Futures fins

Futures Fin Box

A long slot is used to secure each Futures fin. A single screw is locked into place with a Futures fin key, the use of the longer anchor is widely accepted to ensure fin durability and prevent breakage. 

What Futures Ride Number is best for me?

To help you get a fin that responds in the way that you want, Futures have introduced a 'ride number' to all of their fins. When looking at Futures fins, use the illustration below to identify how they will behave in the water.

Futures ride number chart

Shop Futures fins

FCS Fins

Close up of FCS I Fin Box

You’ll spot two circular plugs that make up the fin box. Each of these has a groove in which match up to the two tabs on the bottom of FCS fins and other compatible fins. The fins are secured using a fin key that locks a small screw at the base of each tab. 

FCS II Fins

FCS II Fins

The newest evolution in fins and fin boxes. No screws required, FCS II uses a pin and rotating barrel to secure the fin. FCS II fin boxes have an adapter that accepts old FCS fins too. The beauty of FCS II systems lies in the quick change – even if you’re on the water you can swap out your fins with ease.

Shop FCS I fins

Shop FCS II fins

What size of FCS surf fins should I buy?

Getting the right size can have a massive impact on how your FCS fin performs in the water. Once you’ve decided on the fin for you, check-out the FCS fin size guide on the product page, using your body weight to determine the best fit for you.

Longboard fins

So, you’re riding a longboard? You should see the standard channel that accepts multiple brands of fin. You should have a long channel at the tail of your board, usually around 10 inches in length. Longboarders change the position of their centre fin depending on their style, the type of waves they’re surfing in and how they want their board to respond. As a guide – if you want more control, move the fin back in the box, and if you want a looser surf feel, bring it forward. Play about with different positions to find your favourite. Keep an eye out for longboard-ready FCS II fins, they have FCS II box tech built into the fin, fitted for a traditional longboard box.

Longboard fin positioning

Shop all longboard fins

Surf fin configuration

Next, let’s do some counting. Have a look at your surfboard’s tail – what fin configuration options are open to you?

What's you fin configuration

Check out our fin config table. There's a full breakdown below.

Fin Configuration Key Features
Single Excellent for control and stability on longboards, turns are longer and drawn-out.
Twin More playful and stylish, adds speed when the waves are small.
Tri/Thruster Most popular - control from centre fin, speed from side fins.
Quad Super-speedy, great for adding drive. Excellent for initiating turns.
5-Fin Versatile, gives you the ability to switch between set-ups to suit conditions.

Single

Pretty self-explanatory. Most longboards house an old-school single fin. Single fins are great for going fast and in a straight line – they’re not the best for turning though.  Single fins offer awesome control and stability when placed at the back of the fin box and if you want that slightly looser feel, you can move the fin forward. You can also rock a 1 + 2 setup where there is a centre longboard fin and two small thrusters on the side. This is for steeper waves or where a tight turn would make the centre fin on its own lose grip.

Shop single fins

Twin

If you’re looking for something a bit more playful, twin fins are a great choice. They’re not the best if you’re looking to ride big waves, but for extra speed on your shortboard with long, drawn-out turns they’re awesome. The lack of a centre fin means less drag, so if you fancy yourself a Rob Machado and want to chase style points, a twin would do the job.

Shop twin fin sets

Thruster/Tri

The thruster, or tri-fin set-up is the most common as it suits all ability levels and works with any board shape. The symmetric centre fin offers control, whilst the toed-in outer fins give you plenty speed. With a tri fin box configuration, you can ride single or twin too, making your set-up super versatile. Tri is the go-to set up for the majority of surfers, with the centre fin giving a solid pivot for those top to bottom manoeuvres.

Shop thruster fin sets

Quad

Looking for a speed boost when the surf isn’t big? Then a quad fin set-up could the answer. The four fins channel water to the end of your board to accelerate it, and because there is no centre fin, there’s nothing to slow things down. The outer fins are near the rails, so they add plenty stability and generate drive through the turn.

Shop quad fin sets

Shop quad rear fin sets

Five Fin

You can pick your ideal set-up if you’ve got a 5-fin configuration. You’re not supposed to use all five boxes, instead change things up to match how you want to surf and what the conditions throw at you. You can ride single, twin, thruster and quad set ups on a five-fin surfboard. The only sacrifice is the weight of the additional fin boxes, but it’s not a major consideration.

Shop all fins

Surf fins in wave

Jargon Busting

There’s a fair bit of fin jargon kicking about. Here’s a breakdown of some of the most used terms we use when talking about surf fins.

Drive

Drive refers to how fast the fin will make your board accelerate through the wave, and how well you’ll carry speed when making a turn. The base measurement determines this –  a long fin base length equates to greater drive.

Pivot

Pivot is your turning radius. A short fin base with longer sweep will give you long drawn out turns, where shorter sweep will you let make quicker turns in the wave. Upright fins will make tighter turns, swept back will give a wider arc.

Hold

Hold is determined by total fin area and depth – the larger the fin area the greater it will hold in the wave. In bigger waves, hold is key for stability and control. A short stubby fin will release easily, whereas a longer fin will hold better before releasing grip.

Measurements in Fins

You’ll also hear terms like base, depth, splay, sweep and area being bandied about too. So, what do they all mean?

Surf fin template

Base

In fins, when we talk about base we are referring to the length of the fin from front to back where it meets the board. As fin base length is increased, your surfboard gets greater forward projection in the wave. A shorter base length means less drive, yet a bit more pivot that’s essential for quick turns.

Depth/length

Depth, as you might expect, refers to the fin’s depth under the water. An increased depth will create hold as your fin essentially anchors you to the wave. Shorter depth will release easier to give the board a looser feeling.

Sweep/Rake

This is the length of the curve of the fin and has the biggest effect on how your board pivots.  Longer rake restricts your board’s level of pivot, so you’ll make longer, sweeping turns. Selecting a fin with a shorter sweep will give you quicker turns and more agile surfing.

Surf fin area and foil

Area

The surface area of the fins or fin set you select can greatly affect the way your board feels. The bigger the fin area, the greater stability your board will have in the water. However, larger fin area means more drag, so less speed. Smaller fin area gives your board speed in the water but these fins are far more difficult to control and therefore a better choice for more advanced surfers.

Foil

If you’ve ever sat over the wing of a plane, you’ll have noticed that it isn’t shaped uniformly. The shape is rounded in certain areas to affect the way air molecules move over the wing to create glide lift. Foil in surf fins does the same by manipulating the way water flows over the surface. Here are the key foils to look out for:

  • Inside
  • Flat
  • 50/50
  • 80/20 and 70/30

Inside

The inside foil shape has a rounded leading face and a concave inside, this adds lift whilst reducing drag, and so is ideal for maintaining speed through the turn. 

Flat

Flat foil fins, unsurprisingly, have a flat inside edge that opposes a convex outer. They offer balance between drive, pivot and hold that’s often favoured by pros thanks to the nimble feel they offer in comparison to the inside foil.

50/50

As you might expect, these are symmetrical. You’ll usually see this shape on single fin set-ups, centre fins in tri set ups or as the two inner fins in a quad. Water flows evenly over these fellas for predictable stability and control.

80/20 and 70/30

Asymmetrical and usually seen in the rears of a quad set up, these foils make for responsive turns and control at the same time.

Toe/Splay

This is the angle of the outer fins when comparing them to the centre fin. Your side fins are “toed-in”, meaning the front of the fin is angled-in towards the middle of your surfboard. This results in increased water pressure on the outside of the fin which in turn boosts board response when you’re in the wave.

Flex

Every fin flexes in a slightly different way depending on what it’s made of and where those materials are placed in the fin. Generally speaking, stiffer fins have a more consistent and stable feel that’s great for all riding abilities. More advanced surfers prefer a fair bit of flex in their fins, to generate speed and give a more playful feel when turning.

Cant

This is the angle that the fin will sit at in relation to the base of the board. An upright fin will give more speed in a straight line but will not be very responsive through turns. A larger angle of cant will give the board more drive through turns.

That's a wrap

There you have it – the mysterious and complex world of the surf fin. As you can tell, there are a load of options available, even within the different fin box systems. The key is to find a surf fin set up that gives you that feeling you’re chasing under your feet!  We hope that you now have a better idea of the fins that are right for you and your surfboard, but as always, any questions at all, get in touch, we’ve got your back.

Fin.

Shop our range of surfboard fins now!