FCS Replacement Fins - Left, Right & Rapid Set

Broken a fin on a river wave, stone bottom or wave-pool entry? Instead of buying a full thruster set, you can replace exactly the fin you lost. Our FCS Replacement Fins are available as Left, Right, or Rapid Set (both side fins only) and fit all FCS1 / Double Tab surfboards.

Side fins break far more often than center fins — especially at the Eisbach, Floßlände, Wellenwerk Berlin, Surf Langenfeld, Urbansurf Zürich and other European river waves. Replacing only the broken fin is up to 70% cheaper than buying a complete set and avoids unnecessary waste.

All fins are made in Germany using recycled, glass-fiber reinforced materials for maximum durability and precise control. Designed with a flat-inside / curved-outside foil, they offer excellent drive and stability in fast, punchy river waves.
Fast shipping across Germany, Austria & Switzerland.

How to tell which fin is left or right?

Just place your fins facing downward with the board nose pointing forward — like in the picture.

  • Left fin → sits on the left rail
  • Right fin → sits on the right rail
  • Middle fin → is symmetrical

The inside edge is flat, and the outside edge is curved.

If you’re unsure, match your fin to the photo — or send us a quick picture of your board.

FCS Replacement Side Fins Mounted on Surfboard – Left and Right – River Surf Setup

Why Replace a Single FCS Fin Instead of a Full Set?

Side fins break more often than the center fin—especially in river waves and wave pools. Replacing only the broken side is cheaper, faster, and avoids unnecessary waste. Our Rapid Set is ideal if both side fins are damaged.

Looking for a full thruster setup? Check our FCS Thruster Sets.

Surfboards with FCS Double Tab Fin Boxes – Compatibility Example

Board & System Compatibility

Compatible with all boards using:

  • FCS1 / Double Tab
  • River boards & wave-pool boards
  • Shortboards
  • Softboards with FCS adapter
  • Wakesurf boards

Popular compatible brands:
Firewire, Libtech, Torq, NSP, Softech, Rivver, Buster … and all river surf brands.

Browse all Surf Fins compatible with FCS1.

FAQ

Find the most frequently asked questions below.

  • FCS1 and Double Tab mean the same thing: the original FCS plug system with two tabs. All our replacement fins fit classic FCS1 surfboards and any softboard with an FCS adapter.

  • The inside is flat, the outside curved. If unsure, send us a photo.

  • No. The rapid sets only contain the side fins. You can select a center fin separately.

  • Yes — they’re built for high-impact river use.

  • Yes, as long as the system is FCS1.

Eisbach Riders Founders with River Surf Fin – Munich

Designed in Munich — Inspired by the Eisbach

Born on the Eisbach river in Munich, we’re a small independent team creating sustainable, high-performance gear for river surfers, ocean riders and SUP touring enthusiasts.

We craft our fins from recycled and bio-based materials, supporting cleaner waters and donating a portion of every sale through 1% for the Planet.

Designed and built in Germany, every product is tested and refined on the river, in the ocean, and on long-distance SUP tours—only gear that truly convinces us makes it into the shop.