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Swim Fin Sizing Made Easy!

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Swimming with fins is an important way to develop your kick and build leg strength.

Read this guide and learn how to get the perfect fit, every time.

Proper Swim Fin Sizing Is Easy

Can selecting your swimming fin size be as straightforward as checking your shoe size?

Not always, but fitting fins shouldn’t be challenging or frustrating.

5 Key Tips For Fitting Fins

Sole To Sole Swim Fin Comparison

Match sole to sole to assess fit.

1. Shoe Size

Start by choosing fin size based on your shoe size. If you wear a size 10 in your daily shoes, begin with a size 10 swimming fin.

Upon receiving your fins, or during your visit to a Kiefer Swim Shop, make a visual comparison by aligning the sole of your shoe with the sole of your fin.

2. Trying On Your Swimming Fins – Dry / Wet


Toe Position

It’s OK for toes to show in the fin’s foot pocket window, but make sure that your toes do not protrude from the foot pocket window.

Dry Fitting – Be Careful!

If you are fitting fins dry, inserting your feet into the swim fin foot pocket is met with ample resistance. Some new fins are “greased” or “powdered” and may not present this issue, but most swimming fins are not.

Swim Fin Fitting

Don’t allow a loose fit! Fins should be snug.

Struggling to enter dry fins may cause you to “size up” unnecessarily, resulting in floppy fins that are inappropriately loose in water.

Wet Fitting – Ideal!

The ultimate approach to fitting swim fins is fitting them in the water and taking them for a spin in the pool.

3. Close, Snug Fitting Swim Fins Preferred!

Fins should fit snugly; if you can fit multiple fingers in the space between fin and skin they are too big. Fins should not be loose. A loose fin will cause chaffing and likely painful blisters in the long run.

4. Between Fin Sizes? Put A Sock In It!

Kiefer Lycra Watersox

Add Kiefer Lycra Watersox to fill unnecessary gaps.

If you find that your feet fall between fin sizes, don’t give up! Grab Kiefer Lycra Socks to fill the gaps. They will add padding and comfort and eliminate uncomfortable rubbing.

5. Not Satisfied With The Fit Of Your Fins? Don’t Worry!

We want swimmers to be happy with the fit of their Kiefer Swim Fins.

Save your receipt! If you are unhappy with the fit of your fins, follow Kiefer’s Returns procedure to exchange/refund fins fit in the water that do not meet your fit expectations.

Kiefer Can Fit You!

There is a good fit for everyone out there. Don’t let one bad fit get you down – try our selection of swim fins to discover what works the best for you and your swim training.

Looking for help choosing a swim fin style? Check out our blog post on how to choose swim fins.

About Emily Milak

Emily Milak is a lifetime competitive swimmer living in Southeastern Wisconsin. Emily is a US National Team champion, NCAA champion, and USMS champion with extensive coaching experience. She is a product development consultant at Kiefer.

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