A surfboard is only as good as its fins – and sometimes they need to be changed. Whether you want to try a different setup or template, replace damaged fins, or prepare your board for new conditions: proper handling of your fin system is essential. In this guide, you’ll learn everything you need to know about changing fins on the most common systems – including FCS I, FCS II, FCS Fusion, Future Fins, “Snap-In”, and classic longboard fin boxes.
Key Takeaways:
- Most problems when changing fins arise from carelessness
- The procedure and necessary tools for changing fins depend on the existing fin system
- Fin screws should not be overtightened, otherwise your surfboard, fin plugs, and fins can be damaged
- With FCS II Longboard Fin, the fin’s position can be adjusted in the water
Changing Fins in 5 Simple Steps:
- Identify your fin system and prepare the appropriate tools. Whether you need a fin key, Allen wrench, or nothing at all depends on the system.
- Carefully loosen the screws – if your system uses them. Avoid excessive force to prevent damaging the thread and ensure a stable, but soft surface.
- Gently pull out the fin, without jamming it. If it gets stuck, work gently and evenly.
- Clean the fin box with a brush or cloth to remove sand, salt, or other foreign objects.
- Insert the new fin correctly: Tip points towards the tail, the fin base sits flat in the plug. Tighten screws – but don’t overtighten.
You'll Need these Tools for your Fin Change
Depending on the system, you’ll need different tools. FCS I, FCS Fusion, and Future Fins require a fin key to loosen and tighten the small grub screws. Depending on the screw head, a flathead or Phillips screwdriver may also be needed (only for longboards or single fins). With FCS II or “Snap-In” from Captain Fin, the fin can be inserted without tools, but additional securing with a screw is possible – and recommended.
Besides the fin key, you’ll need a soft surface to prevent scratches or damage to your board. Optionally, a towel for hand protection is useful, as the sharp edges of the fins can cause cuts. Alternatively, T-shirts, boardshorts, or surf ponchos are also suitable. Alternatively, a fin puller can also help, which levers the fins out of the fin box.
A lubricant makes it easier to remove the fins from the boxes. Preferably natural-based, as residues can remain even after cleaning.
You may need fine sandpaper to prevent future fin jamming (if fins are already very difficult to insert into the plugs). For jammed fins that are already inserted, a rubber mallet can help. However, you should be very careful, as the fin plug can also be damaged when using a hammer.
Fin Arrangement & Alignment – which Fin Goes where?
To avoid inserting the fins incorrectly, make sure the tip of the fin points towards the tail – i.e., backwards.
The center fin (Center Fin) has a symmetrical convex curve (50/50 foil), while the side fins are flat on the inside (flat foil) and curved only on the outside. This regulates water flow (hydrodynamics) and improves the riding feel, which increases performance through more stable turns.
When inserting, therefore, make sure that the curved side faces outwards and the flat side of the fins faces inwards.
In a thruster setup (3 fins), the center fin sits in the middle at the back, and the two side fins are positioned laterally at the front. The quad setup has 4 side fins; here, the larger fin is placed further forward and the smaller fins (rear fins) further back.
Which Fin System Do I Have?
You can identify which system is installed in your board by the shape of the fin plugs. Here’s an overview of the most important systems:
- FCS I: Depending on the size of the fin, this system uses one to three individual round plugs. The FCS I plug is flush with the board’s lamination.
FCS Fusion: An octagonal white-greyish fin plug that is laminated into the board. - FCS II: Similar shape to the Fusion plug. It is only slightly longer, but narrower and usually has a perforated look.
- Future Fins: Elongated, narrow shape along the fin base.
- Longboard Fin Box: The largest fin box for single fins, with an integrated track. It allows for variable positioning of the fins within the track.
- FCS II Longboard Fin: Here, the FCS II fin system is integrated into the fin itself and is compatible with longboard fin boxes.
The newest fin systems on the market are Fin-S and “Snap-In” Captain Fin. Globally, they are not yet relevant. In our blog post: Which is the best fin system? You’ll learn more about the pros and cons of the different systems!
How to change your fins – guide by system
Dual-Tab system with FCS I & FCS Fusion – classic screw change
Two different systems, one way to change the fins. Here’s how:
- Loosen the screws with the fin key
- Carefully pull the fins upwards out of the plug
- Clear fin plugs of foreign objects like sand
- Insert new fins completely into the corresponding fin plugs with the tip pointing towards the tail and tighten.
Note: Typically, two FCS I plugs are installed per fin. For smaller fins, like Twinzers, only one plug is installed, and for larger keel fins, three plugs are installed.
FCS II – the tool-less click system
No fin key is necessary to change the fin, but it is recommended! Here’s how to change FCS II fins:
- Loosen the screws with a fin key, if they are additionally secured.
- Pull the fin firmly upwards and towards the nose, forwards. One hand grips the fin (grasp the fin tip), the other rests on the board. It prevents the surfboard from lifting when removing.
- Remove sand and other foreign objects from the plug, especially ensuring a clean area of the fastening mechanism.
- Insert the new FCS II fin, notch first, into the groove in the corresponding plug and gently press the rear part into the plug. If you hear a click, you know the fin has engaged in the fastening mechanism (at least you should feel it click into place).
- Optional: For more security, additionally secure the fin with a screw. Use the screw thread that is closer to the tail for this.
The FCS II fin system is often criticized for not being secure: surfers repeatedly publish experience reports, including on Reddit, about lost FCS II fins. You can find out how secure the FCS II fin system is in our blog post. We recommend prioritizing safety; it’s better to invest a few more seconds when changing than having to buy new fins – especially annoying if you lose the fins on a surf trip.
Properly changing future fins single-tab system
The change is performed similarly to the dual-tab system, but only one screw is needed. Whether you have Future Fins fins or fins from a third-party supplier with the single-tab system, it doesn’t matter, the process is the same. For a secure change, follow these steps:
- Loosen screws with the fin key.
- Carefully press the fins downwards at the tip until the front part of the fin base is levered out of the fin plug. If it protrudes, you can remove the fin at an angle between 15° to 25° forwards.
- Clear Future fin plugs of foreign objects like sand.
- Insert the new single-tab fin into the notch, at the back of the fin base, into the groove of the corresponding fin box and carefully press the fin completely into the plug.
- Tighten the screw to secure the fin with the fin key.
Important: For fins with a long base, you need to be careful: press the fin downwards more gently. Otherwise, you’ll damage the glassing just behind the fin plug.
Properly Changing Longboard Fins (Single Fin)
Single fins installed on longboards, mid-lengths, bonzers, and duos have different fastening systems – the classic system and the FCS II Longboard Fin System. There are also different fastening mechanisms between these two. Here you’ll learn everything important about both systems:
Changing classic longboard fins (US & Bahne Box)
Changing longboard or single fins is generally the same. When mounting or dismounting, the main thing is where the fin dowel for insertion into the fin box and where the fin screw hole for fastening the fin are located. The two elements are reversed depending on the manufacturer. Both elements are either at the end or at the beginning of the fin base.
- Loosen the fin screw, with the appropriate tool, at the front or back of the base (manufacturer-dependent).
- To remove the fin from the fin box, guide the dowel (also roll or spring pins) along the fin box track to the fin box opening (in the middle of the box).
- Position the plate with, for example, the fin key as needed, if you want to mount the fin in a different position or if the position of the fin dowel and the fin screw hole are reversed (depending on the manufacturer).
- Then insert the fin with the dowel into the fin box opening and slide it to the desired position so that the fin screw hole is directly above the washer’s thread. Lightly screw the fin into the thread and also correct the position before tightening the screw.
A fin key is usually necessary to tighten the screw. However, depending on the screw, a flathead or Phillips screwdriver may be required. But there are also hand screws that allow for tool-less fin changes for single fins.
Mounting and Dismounting FCS II Longboard Fin
While FCS II is not the only tool-less single fin system, it is designed to allow for readjusting the fin position in the water. If you change the fin on land, be sure to use a soft surface to avoid damaging the board.
- Dismount the fin: Grip the fin tip with one hand, the other hand lies flat on the board. Then pull the fin firmly yet carefully upwards at the tip and slightly forward towards the nose. At the same time, the other hand counters to prevent the board from lifting.
- Guide the dowel at the front part of the fin through the fin box opening in the middle of the longboard fin box to remove the longboard fin.
- Insert the new fin over the pin into the box and guide it forward along the track to the desired position.
- With gentle but firm force, press the rest of the fin’s base into the fin plug until the fastening mechanism clicks into place.
The clicking of the tool-less mechanism of the FCS II Longboard Fin is less likely to be heard compared to FCS II. However, you should feel the click with the hand that guides the fin into the plug. Unfortunately, with the longboard version of the FCS II system, additional securing with a grub screw is not possible.
There are no compatibility issues with the system for single fins. All systems are compatible with longboard fin boxes; there are only differences in fastening.
Surfers choose the fin position in the box as follows:
- At the end of the fin box, near the tail: more stability when surfing, especially popular for noseriding
- At the beginning of the fin box, closer to the nose: loose surf feel and easier turns
- Individual fin box position: the middle is a balance between stability and hold, as well as maneuverability
Our recommendation: Play with the fin’s position to find the best spot for you. To do this, place your fin at different points on the track and pay attention to how the different positions feel when surfing. Different fin templates may require different positions in the fin box – matching your surf style.
What to Do if the Fin Gets Stuck?
The most common problem when changing fins is jammed fins. The causes are usually sand, salt deposits, or minimal manufacturing tolerances. The following tips help:
- Spray or drip lubricant between the plug and the fin (then clean thoroughly to avoid taking lubricant residues into the ocean – preferably use a natural lubricant)
- Pull evenly with both hands & do not apply jerky force
- Try to wiggle the fins back and forth to loosen them (only minimally, otherwise the fin box can be damaged
Gently assist with a rubber mallet and soft cloth
If you follow these tips, you’ll prevent fins from getting stuck in your board’s plugs! However, should a fin get stuck in the fin box, you’ll know how to handle it.
How Can I Prevent Fins from Getting Stuck?
You can prevent annoying fin jamming as follows:
- Clean fins and fin plugs: Foreign objects like sand, sea salt deposits, and other debris have no place in the plug; they often cause fins to get stuck.
- Regularly remove fins: This prevents foreign objects from accumulating in the gaps over time.
- Fix manufacturing tolerances yourself: Fin tabs that are slightly wider than usual are difficult or impossible to insert into the fin plugs. You should sand down the tabs evenly on both sides with fine sandpaper.
With these tips, you’ll prevent fins from getting stuck.
Fin Compatibility – which Fin Fits which System?
With so many fin systems and fin manufacturers, it’s easy to lose track. This table shows you which fins are compatible with which system:
|
System / Fin
|
FCS I
|
FCS Fusion
|
FCS II Fin System
|
Future Fins
|
“Snap-In”
|
FCS II Longboard Fin
|
Single Fin
|
|---|---|---|---|---|---|---|---|
|
FCS I
|
compatible
|
compatible
|
not compatible
|
not compatible
|
compatible
|
not compatible
|
not compatible
|
|
FCS Fusion
|
compatible
|
compatible
|
not compatible
|
not compatible
|
compatible
|
not compatible
|
not compatible
|
|
FCS II Fin System
|
compatible*
|
compatible*
|
compatible
|
not compatible
|
not compatible
|
compatible*
|
not compatible
|
|
Future Fins
|
not compatible
|
not compatible
|
not compatible
|
compatible
|
not compatible
|
not compatible
|
not compatible
|
|
compatible
|
compatible
|
Content
|
Content
|
not compatible
|
not compatible
|
compatible
|
not compatible
|
|
longboard fin box
|
not compatible
|
not compatible
|
not compatible
|
not compatible
|
not compatible
|
compatible**
|
compatible
|
*no tool-free securing possible, only by screwing them tight.
**no additional securing with a screw possible
If your board has FCS II plugs and you have dual-tab fins, you can optionally use the FCS II compatibility kit. They fill the void in the plugs and prevent unwanted water turbulence.
Proper Care of Fins and Plugs
If you take good care of your equipment, it will extend its lifespan and you will enjoy your surfing equipment for a long time. In addition to using it carefully, this also includes regular maintenance. It is worth rinsing the fins after surfing and occasionally removing them and cleaning the plugs.
Very important: Do not tighten the screws too tightly – otherwise there is a risk of cracking. If the screws are rusty, you should replace them immediately before they cannot be loosened without major effort.
Our Opinion and Experience
Again and again we have experienced surfers putting surf wax on the tabs of their fins to get them in and out of their fin plugs more easily. This may help with mounting the fins – but it is very deconstructive when disassembling them. The sticky mass makes it much easier for sand, sea salt and other dirt as well as debris or splinters from fins to collect. It is better to not use surf wax! Better is a liquid lubricant on a natural basis.
To prevent damage to the glassing when changing from larger keel fins, you should place a flat credit card (without embossing) under the fin, at the end of the extended base, on the board. If you hit the credit card with the fin, the force of the impact is distributed. A crack in the glassing is less likely this way.
Most problems when changing fins arise from carelessness. Those who are careful and work with the right tools have the least stress.
Changing the fins with screws only takes a few seconds longer, but sits rock solid. But make sure that you do not tighten the screws too tight. Otherwise, too much pressure is put on the fin plug and it can wear out in the long run and the fin can become brittle and damaged. Here you can see what a damaged fin can look like due to tightening the screws too tightly:
No matter which fin system you surf with, dare to try out different fin templates. Even with longboard fins, it is worth experimenting with the positioning: Even a few centimeters forward or backward can have a major impact on handling. Both can greatly improve your surfing experience.
For us, it has also proven useful to have spare equipment for changing fins with us – especially on surf trips. Spare screws, another Allen key or fin key and some grub screws are light and take up hardly any space.
Summary – Changing Fins Made Easy
Changing fins is not rocket science – if you know your system, it can be done in a few minutes. Whether FCS, Future or Longboard: With a little practice, the right tools and a little care, your setup will remain durable, safe and ready for performance. This way you can always surf your surf session with your desired fins and increase the longevity of your surfboard – whether you are just starting out or already on the waves as a pro surfer.
