A Comprehensive Surfboard Fin Guide

Have you ever wondered how many meanings there are for the word “fin”?

A few years ago, I asked my mom to bring me a new set of Futures fins when she was preparing to visit me in Costa Rica. This sparked a lively debate over whether they would fit in her suitcase. I was sure they would—until we FaceTimed, and I realized she thought I meant my long-abandoned free-diving fins.

There are many types of fins in the aquatic world: snorkeling fins, ultra-long free-diving fins, bodysurf fins, and lastly, surf fins. 

Unlike the fins used on your feet to propel your body through water, surfboard fins are more similar to a boat’s rudder or a fish’s tail fin. They help with steering, stability, and directional control in the water, allowing for smoother turns and better maneuverability.

While surf fins aren’t unique in concept, decades of innovation in design and materials have transformed them into highly specialized and technical surf gear.

Most beginner surfers would struggle to say how many fins their board has based on feel, let alone the unique shape of those fins. Luckily, I’ve been able to experiment with over a dozen unique twin fin sets thanks to the Costa Verde Surf Shop. 

Still, as a lifelong surfer, the most I can describe about how these fins feel is vague and poorly defined. Some feel “loose,” while others feel “drive-y.” And unless you are an excellent surfer, interested in surf tech, or a hydrodynamicist, you probably won’t notice much difference either. 

However, understanding the basics of fins and fin types is an important step in any surfer’s journey. In this beginner’s guide, I’ll break down everything I’ve learned about surfboard fins from the fine folks at Costa Verde Surf Shop.

Whether you’re just starting or looking to upgrade your gear, this guide has you covered.

What are Surfboard Fins, and What Do They Do?

Simply put, Surfboard fins are small, fin-shaped attachments on the underside of a surfboard that help with steering, stability, and control while riding a wave. They work like the rudder on a boat, allowing you to make smoother turns and stay balanced in the water.

On the more technical side, surfboard fins create hydrodynamic lift, providing stability and directional control by reducing lateral slide and enhancing maneuverability. As water flows over the fins, they generate drag and resistance, helping the rider maintain control while performing sharp turns. 

The fins’ placement, size, material, and shape all affect the board’s performance. Smaller fins generally allow for looser, more responsive turns, while larger fins offer greater hold and drive, especially in powerful waves. 

Fins also affect how easily the surfboard turns by acting as a balance point (a pivot point). They help the board respond to body movements, like shifting your weight to steer or making sharper turns.

Types of Surfboard Fin Setups 

Just as we covered the many different types of surfboard shapes, there are also different fin setups. If you’re interested in learning which is best for a beginner, head over to our post on the best beginner surfboard.

Remember, each fin set-up has pros and cons depending on the type of wave you are surfing and your surfing goals. Learn about the different types of surf breaks before deciding which fin set-up is best for you. 

Single Fin

A single fin is one large fin positioned in the center of the board near the tail. Fins used in this configuration are typically long and wide, designed to provide stability and smooth tracking or the board’s ability to maintain a straight line. Single-fin setups are often found on longboards or retro-style boards.

Single fins generally offer a smooth and stable ride, great for longboards and a more classic surfing style focused on straight-line speed, nose riding, and flowing turns.

Twin Fin

Two fins, one placed on each side of the board’s tail. Proper placement of twin fins is close to the board’s tail and can vary from keels (large, wide-based fins) to uprights (more vertical shape). Twin fins can be found on old-school fish boards as well as high-performance short boards. 

A two-fin setup is known for being fast and loose, allowing for quick, sharp turns and more playful maneuvers, and is considered fun for smaller, weaker waves (unless you’re Toryn Martin or Ryan Burch).

Thruster

A thruster setup has three fins—all the same size. The center fin is slightly forward from the tail, while the two side fins are set symmetrically on either side. The Thruster setup is the most common on performance shortboards, hybrid boards, and longboards.

The thruster configuration is generally considered the highest-performing of the fin setups, providing a balanced combination of speed, control, and maneuverability. Professional surfers on the WSL Championship Tour mostly use thrusters, followed by quads.

Quad

This setup consists of four fins, two on each side of the board. The two rear fins are positioned closer to the tail, while the front fins are placed slightly ahead and towards the rails. The fins used for this setup consist of smaller, more equal-sized fins, often with a more upright angle to increase speed and drive. They are typically used for shortboards, especially for powerful waves.

Eliminating the center fin reduces drag, creating a faster, more agile setup with increased control and drive. This setup is particularly well-suited for hollow waves.

Five Fins or Tri/Quad

This fin setup has options for both a thruster or quad setup. Boards with five fins have a combination of three fin boxes in the center and two additional fin boxes on the sides. A fin box is a slot or box built into the bottom of a surfboard with removable fins attached. It allows you to switch out fins based on preference or wave conditions. This configuration is used on various boards, offering the flexibility to switch between thruster or quad setups. 

It’s true that there are surfers who experiment with “alternative” fin setups, such as a 2+1 or a 4+1. No matter how they are configured, it’s unusual to see more than five fin boxes on a board.

Elements of surfboard fins

Rake

Rake refers to the degree of backward tilt or angle of a surfboard fin from its base to its tip. 

A fin with more rake curves backward, providing smoother, drawn-out turns, more stability, drive and hold during carving maneuvers. It’s ideal for maintaining control in bigger waves or when executing long, flowing turns.

A fin with less rake or a more upright design allows quicker, tighter turns and snappier, more responsive surfing. These fins are typically used in smaller or steeper waves where agility and quick directional changes are key.

Cant

Cant refers to the angle at which a surfboard fin is tilted outward from the bottom of the board when viewed from the rear. Cant influences how easily the board pivots and reacts to rail-to-rail transitions, with higher cant making the board more maneuverable and lower cant offering more speed and tracking.

Fins angled more outward (more cant) provide looser, more responsive turns and increase maneuverability. This setup is great for playful surfing in smaller waves or when you want more control for quick, sharp turns. 

Fins with little to no cant (near vertical) generate more speed and drive in a straight line, offering less resistance. This setup is ideal for down-the-line speed and riding bigger, faster waves.

Splay

Splay refers to the outward angle of the side fins on a surfboard when viewed from above. It is the horizontal spread of the fins, where the tips point away from the board’s centerline.

When the fins are angled more outward, it enhances maneuverability, allowing for smoother, more fluid turns. This setup is great for carving and maintaining control during rail-to-rail transitions.

Fins that are more parallel to each other, with less splay, provide better drive and speed down the line. They focus the water flow in a straighter direction, reducing drag, which is ideal for maintaining speed in bigger, more powerful waves.

Toe

Toe refers to the inward angle of the surfboard’s side fins, where the front of the fin points slightly toward the board’s centerline. 

Fins with more toe angle create increased water resistance, which helps the board turn more easily and enhances maneuverability. This setup is ideal for making quick, responsive turns in smaller or steeper waves.

Fins with less toe angle (closer to parallel) generate more speed and drive in a straight line, as the water flows more efficiently along the fins with less resistance. This setup is better for maximizing speed, especially in larger, more powerful waves. 

Base Length

Base length refers to the length of the bottom edge of a surfboard fin, where it attaches to the board. The base length of the fin influences how much speed and power you can generate, with a longer base focusing on drive and a shorter base emphasizing maneuverability.

Fins with a longer base provide more surface area, which helps generate greater drive and speed in a straight line. It allows the board to hold more energy when turning, making it ideal for down-the-line surfing, especially in powerful waves.

A shorter base allows for quicker, sharper turns and a more responsive feel, as there is less surface area to resist the water flow. This setup is perfect for tight, snappy maneuvers and quicker direction changes, especially in smaller or steeper waves.

Foil

Foil refers to the shape of the fin’s cross-section, which affects how water flows over it. Fins with more curvature or thickness toward one side (typically the outside) generate lift and speed, helping with smoother turns. 

Fins with a flat inside face and curved outside face offer more control and stability, especially in bigger waves.

Flex

Flex is how much the fin bends or flexes under pressure during a turn. Flex determines how much energy the fin stores and releases during turns, affecting how reactive or stable the board feels.

More flex creates a spring-like effect, giving the board a looser, more playful feel and allowing for snappier turns. This makes it ideal for smaller waves where quick, responsive moves are key.

Less flex (stiffer fins) provides more control and stability, especially at higher speeds.

Height (Depth)

Height, also known as depth, is the vertical measurement of the fin from the base to the tip. 

Fins with more depth extend deeper into the water, offering more hold and stability. They help the board grip the wave face better during turns. A shorter height provides a looser feel, allowing for easier turns and quicker transitions in smaller or weaker waves.

Pivot

Pivot refers to the fin’s ability to help the board make sharp, quick turns. 

Fins with a more upright design have a greater pivot point, allowing for tight, fast direction changes and a snappier feel. This is great for surfers who need quick, aggressive maneuvers in the pocket. More pivot works well at beach breaks and suits light-footed, quick, or grom surfers.

How to Choose the Right Surfboard Fins for Your Board

Surfboard Fin Setup

Choosing the right fin setup depends on your board type, surf style, and typical wave conditions. A single-fin setup is ideal for longboards and a more classic, stable ride, while twin fins provide speed and agility for playful maneuvers in smaller waves. Thruster or quad setups offer stability, control, and maneuverability, making them popular for high-performance boards.

Size

When choosing fin size, consider your weight, skill level, and wave conditions. Futures Fin Sizes offers a helpful guide: XS for surfers weighing 75 to 115 lbs, S for 105 to 155 lbs, M for 145 to 195 lbs, and L for those over 180 lbs. 

FCS has a similar guide: XS for 120 lbs, S for 135 lbs, M for 150 lbs, L for 180 lbs, XL for 200+ lbs.

Larger fins provide greater hold and control in powerful waves, while smaller fins allow for a looser, more responsive feel, ideal for quick turns in smaller waves.

Fin System

A fin system refers to the mechanism that attaches surf fins to the board. These systems are typically designed with fin boxes or plugs embedded into the board, which allow for fins to be secured with screws or clips, and easily swapped out. 

Futures and FCS are the two most common fin systems.

A fin box is a slot or insert built into the bottom of a surfboard where removable fins are attached. It allows surfers to switch out fins depending on wave conditions or personal preferences. 

Fin boxes offer flexibility in experimenting with different fin setups. The alternative to fin boxes is glass-on fins. Glass-ons are permanently fixed to the board, typically on retro or classic boards. Glass-on fins provide an awesome look and seamless feel in the water but lack versatility as they can’t be removed for travel or swapped out.

FCS Fins

Uses dual plug holes for each fin, allowing fins to be attached with a screw-in mechanism, offering flexibility for quick changes. The updated FCS II system has a mechanism that lets you quickly snap fins in and out without screws. Both types are compatible with various fin shapes and sizes.

Futures Fins

Uses a single fin box where the fin slides in a track and is secured with a set screw. This system lets the surfer easily swap out fins and is compatible with a wide range of fin shapes and materials. 

Types of Fin Construction

Fiberglass Fins

Fiberglass fins are strong, durable, and have excellent flex properties, making them ideal for powerful turns and stability in larger waves. Due to their smooth, predictable feel and durability, experienced surfers often prefer them.

Composite Fins

Made from a blend of materials like fiberglass and plastic, composite fins balance strength and affordability. They provide good flexibility for beginner to intermediate surfers and offer solid performance without the higher price tag of pure fiberglass or carbon fiber.

Carbon Fiber

Carbon fiber fins are extremely lightweight and responsive, making them popular for high-performance surfing. Known for their stiffness and speed, they allow quick, powerful maneuvers and are best suited for advanced surfers in fast, demanding waves.

Plastic

Plastic fins are the most affordable and flexible option, ideal for beginners or casual surfers. While they lack the stiffness and performance of other materials, they’re forgiving and durable, making them perfect for soft-top boards or shallow surf zones.

Wood Fins

Wood fins are aesthetically unique and offer a more natural feel in the water. They are often paired with eco-friendly surfboards. Wood fins tend to be stiffer than plastic but less so than fiberglass, providing a balanced performance ideal for classic-style surfing.

Keep it Simple

Don’t overthink it! All FCS and Futures fins will make excellent beginner fins and last decades. Remember, it’s not the fins that will determine your success; rather, it is your patience and perseverance to learn a new sport and experiment with finding the right set-up for you. 

Try as many different fin types as possible. Borrow boards, go to a surf camp, or buy used boards to gain experience and comfort on various setups. This will help you determine which board is best for you and give you the confidence to invest in a long-term, custom-built piece of art, and matching fins! 

Most experienced surfers have various fins that suit different beaches, conditions, and moods of the surfer. Enjoy teaching yourself how to surf—it’s free and easy! 

If you still want help progressing with practical guidance and a streamlined process, consider joining one of our award-winning surf camps at Bodhi Surf + Yoga. 

We have a boardroom waiting for you!