Arena Powerfin Pro Size Guide

Arena Powerfin Pro fins are sized by international shoe size (EU equivalent) and foot length in millimetres. The size chart below also includes USA, UK, and AUS shoe size equivalents as a secondary guide — however, foot length is the most reliable measurement for fin sizing as shoe construction varies considerably between brands and styles.

The Powerfin Pro has an open heel design, which provides excellent ankle flexibility and suits a wider range of foot shapes than closed-heel fins. If your foot length falls between two sizes, size up for a more comfortable fit and to avoid restriction during training.

Tip: to test your fin size, sit on a chair, extend your legs and flex your ankle and foot out — this is your swimming position. Fins are not shoes, so standing in them will not give an accurate size test.

Measure your foot length to find the correct fin size. Do not rely on shoe size alone — always measure foot length for the most accurate fit.

1. 1
   Stand on a piece of paper with your toe against a wall. Make a mark at the end of your heel — this is where the open heel strap of the fin will sit.
2. 2
   Measure the distance from the wall to your heel mark in millimetres. Use this measurement to find your size in the table below.
3. 3
   If your measurement falls between two sizes, size up for a more comfortable fit during training.

Fin sizes shown are international (EU equivalent). Shoe size is a secondary guide only — always use foot length for the most accurate fit. If you are between sizes, size up. Foot cavity dimensions show the internal length and width of the fin pocket.

The Powerfin Pro features an open heel design for maximum ankle flexibility. Follow these steps to put them on correctly and avoid overstretching the silicone.

1. 1
   Push the fin pocket fully onto the foot before adjusting the heel — slide your foot in as far as it will go before touching the heel strap.
2. 2
   Position the open heel strap around the back of the ankle — the strap should sit comfortably in the achilles arch without digging in.
3. 3
   Check the fit in a swimming position — sit down, extend your legs and point your toes. The fin should feel secure and allow free ankle movement. If it feels tight or restricted, try the next size up.

Arena Powerfin Pro fins are made from 100% silicone and are PVC free. Avoid walking on rough pool surrounds or abrasive surfaces, which can accelerate wear on the silicone blade.

• The inclined short blade is designed for a high-frequency kick — do not use these fins for long, slow kick sets. They are most effective for sprint kick drills, vertical kicking, and underwater phase work.
• The open heel provides greater ankle flexibility than closed-heel fins. This allows a fuller range of motion on both the upward and downward kick — focus on ankle mobility to get the most benefit.
• Use Powerfin Pros for vertical kick sets to train your underwater dolphin kick and improve body position — a key training tool for competitive swimmers focusing on their push-off and breakout.
• If you are new to training with fins, introduce them gradually — short sets at first (e.g. 4×50m) and build volume as your legs and ankles adapt to the increased resistance.
• The 100% silicone construction is PVC free, chlorine resistant, and durable. Rinse in fresh water after every use and store flat, away from direct sunlight and sharp objects.
• Avoid walking on rough or abrasive surfaces such as pool surrounds or concrete, which can damage the silicone blade over time.
• Unsure? Contact our team or call +44 1827 330600.