You’ve just bought a new pair of snorkeling fins. You tried them on at home and they fit your feet perfectly! And yet, when you finally get in the water with them for the first time they start slipping off your feet mid-kick! What happened? If I’m on a snorkeling tour, I’m almost guaranteed to spy a lost rental fin floating by at some point. The thing is, how your snorkeling fins should fit is a bit different from how you fit shoes or other footwear. But with a bit of know-how, you won’t have to worry about frantically chasing after lost fins on your next snorkeling adventure!
How should your snorkeling fins fit?
Your fins should have a snug fit on your feet. Just like hiking shoes, a fit that’s too loose will result in uncomfortable chafing and even blisters. At worst, your fins may even slip off while swimming! But how snug is snug enough? You should struggle to fit more than a couple of fingers into the foot pocket while wearing your fins. Otherwise, the fins are too big. However, if your fin is so tight that it’s tricky to get even one finger into the pocket, or if your toes feel cramped for space, then the fins are too small for you.
Testing the fit of your fins in-store
First off, if this is your first time buying snorkeling fins, I highly recommend you visit a proper dive shop. That way, you’ll have a broad selection of quality models to choose from. There will also be knowledgeable staff (most likely experienced divers and snorkelers themselves) available to help you find the best pair for you.
Related post: Where to Buy High-Quality Snorkeling Gear
If you don’t live within an accessible distance of a dive shop, then the next best thing is shopping at a dedicated online dive shop. For example, I prefer Leisure Pro for shipping in the US and Canada. Simply Scuba is an excellent option for shipping throughout Europe from the UK. These sites not only have a great selection, but they’re full of useful information (expert reviews, blog posts, videos, Q&As, etc.) that you wouldn’t find at a general sports store. Online dive shops also understand that testing the fit of your fins is critical and will usually have an exchange policy if your fins aren’t the right size.
How full-foot snorkeling fins should fit
Full-foot fins have a complete foot pocket that fits around your heel and ankles. This is the kind of fin that most snorkelers will want as they’re lighter and can be worn barefoot.
To begin with, try on a pair of full-foot fins that is the same size as your shoes. You can even line up the sole of the shoe you’re currently wearing with the sole of the fin to see how closely they match. Pay attention not just to the length of the foot pocket, but also how wide or narrow it is compared to your shoe.
Fins come in many different styles, so some foot pockets will be wider or narrower than others. If you lean towards narrower or wider than average with other footwear, then you may need to try a few different models to find one that suits your foot shape.
Related Post: Full-Foot Vs. Open-Heel Fins For Snorkeling
If you’re going to be wearing the fins barefoot, then try them on barefoot in-store too! You will probably wriggle and struggle somewhat to get them on, but that’s ok so long as they are comfortable when on fully. When your feet and fins are wet, getting them on will be much easier. However, a fin that slips easily onto your foot when dry may slip off when wet!
Once the fins are fully on your feet, they should feel snug but not too tight. Your feet will naturally shrink a bit in the water as they cool, so erring a little on the tight side is best. A snug fit will also reduce chafing and slipping around your ankle.
Use fin socks for extra comfort, insulation, or if you’re between sizes
Fin socks are made of lycra or thin neoprene (1-2 mm). You slip them over your feet just like regular socks, and you can wear them with either full-foot or open-heel fins.
If the fin you’re trying on feels just a bit loose (because you’re between sizes, for example), then a fin sock can add just enough extra volume to your foot to make a perfect fit. Some folks also find they just naturally tend to get cold feet, even if swimming in tropical water. If that’s you, then plan to get some fin socks with your fins!
Related Post: Wearing Socks With Fins (Choosing Thickness, Styles, and Materials)
Personally, I like to wear fin socks with my fins just for the comfort factor. They do a great job protecting all those awkward bony bits around my ankles from chafing on the foot pocket. These are the socks I wear with my closed-foot fins (Leisure Pro link). The low-cut ankle is great for warm, tropical water and the 2 mm neoprene is just thick enough to secure a snug fit for my narrow feet.
If you want fin socks, then be sure to try on your fins while wearing the socks you want! How your snorkeling fins should fit depends on whether you will be wearing them primarily barefoot or with socks. You may need to size up from a fin that fits you barefoot, especially if the sock is thicker than 1 or 2 mm.
Tip: Remember to always double-check the sizing guides for the manufacturer of whichever fins you’re considering! There is often variation among manufacturers so a US women’s size 8, for example, may not be exactly the same from one brand to the next!
How open-heel snorkeling fins should fit
Open-heel fins don’t fully enclose your foot like a full-foot fin. They are more like a classic slipper. Your heel will stick out a couple of inches beyond the sole of an open-heel foot pocket. The top edge of the pocket will roughly line up just in front of your ankle joint. A strap comes around your heel to keep the fins in place.
One of the key differences between open-heel and full-foot fins is that open-heel fins are usually worn with dive boots. Dive boots are made of neoprene, but unlike fin socks, they also have a treaded rubber sole. Because the dive boot adds to your foot size considerably (more than a fin sock), you must try on open-heel fins while wearing dive boots. If you don’t already have dive boots, choose a properly-fitting pair in the dive shop before trying on open-heel fins.
Even so, some open-heel fins are designed to be worn barefoot or with just a thin fin sock. This is particularly true for open-heel fins designed for snorkeling rather than SCUBA. Online descriptions will usually indicate if an open-heel fin can be worn barefoot. In a dive shop, you can ask one of the staff to point you towards open-heel fins that don’t need boots.
Because of the strap, open-heel fins are a bit more forgiving when it comes to size variation. Like full-foot fins, however, you still need to make sure that the foot pocket is snug around the parts of your foot it covers, and that the sole is the right size. You don’t want your heel sticking out over the edge of the sole too far (fin is too small) or the top edge of the foot pocket cramped against your ankle (fin is too big).
How tight should the fin strap be?
The fin strap on an open-heel fin should be just tight enough to keep the fin on your foot. If you need to tighten the strap excessively, then the foot pocket may be too big for you.
With the correct tightness, you should be able to put on and take off the fins by pulling the strap over the back of your heel. Ideally, you shouldn’t need to buckle and unbuckle the strap each time. Doing this may be tricky when your fins and boots are dry but should be easier once they’re wet.
Related Post: 5 Reasons You Should Upgrade Your Fins With Spring Straps
How your snorkeling fins should fit in the water
When you’ve found a good candidate pair of fins, flex and wiggle your ankles while wearing them. Try to replicate the shape your feet will be in while kicking. Make sure there’s no uncomfortable digging or chafing when you flex your ankle.
A well-fit fin will pivot up and down with your foot. The hinge of that pivot point will be roughly in line with the center of your ankle. If your fin is too small or too large, that pivot point will shift forward or backward respectively. As a result, there will be an imbalance between the use of the calf and shin muscles on your legs, which can lead to cramps.
Now it’s time to get your feet wet!
Try out your new fins in a pool if possible!
Similar to your mask and snorkel, you should only be putting on your fins after rinsing them. You may even put them on while in the water directly. If you’re wearing fin socks or dive boots, however, put your socks or boots on before getting wet! Neoprene slides over skin much more easily when dry!
Compared to when you tried on your fins in-store, you’ll probably notice that the fins are easier to slip over your feet when wet. Even so, they should still feel snug and comfortable, not too loose. Ideally, you should be able to swim around with them for a couple of hours (a typical snorkeling tour) without getting any chafing or sore spots.
Practice how to kick with your fins
Even if you’re a strong pool swimmer, kicking with fins correctly takes practice. I mean this not just in terms of technique, but in being aware of their physical presence in the water. Learning to think of your feet as taking up several times the space they usually do takes some getting used to!
You also need to develop buoyancy control, so you can be deliberate and precise about your body’s position in the water.
Ideally, you will have some time to practice finning technique and buoyancy control in a pool at home or at your hotel before your expedition. Unfortunately, casual snorkelers usually don’t learn or are even aware of these skills. That’s why SCUBA diving websites and blogs are the best places to start understanding them. Pay special attention to mastering your frog kick and your breath control. Learn to stay prone and floating as much as possible. If you must come up to tread, be sure to tuck in your knees to keep your fins off the seafloor or coral.
Related Post: Proper Kicking Technique for Snorkeling
Summary: How Your Fins Should Fit
- Try on your fins at a dive shop if possible. Otherwise, order online from a dive shop with a clear exchange policy in case the fins don’t fit
- Full-foot fins should roughly match your shoe size and are typically worn barefoot
- Full-foot fins will be tricky to get on while dry and should feel snug
- Wear full-foot fins with fin socks for extra comfort, insulation, and a more precise fit
- Open-heel fins are usually worn with dive boots, but some can be worn barefoot. Make sure you know which kind you’re trying on!
- Try on open-heel fins while wearing the dive boots you plan to use with them
- Open-heel fins should have a snug fit without you needing to over-tighten the strap
- Your fins will be easier to take on and off in the water, but they should not be prone to slipping off while you’re swimming
- Your fins should be comfortable enough for you to swim for a couple of hours without getting chafes or sore spots
Ultimately, when it comes to how your snorkeling fins should fit, comfort is king! You can probably recall some personal experiences you’ve had with poorly fitting footwear. Whether it was blisters on a hiking trip or sore feet from insufficient arch support, the wrong footwear can make or break your day!
The most important thing about your fins is that they are comfortable – both on your feet and while swimming with them!
Final Tip: Make Sure Your Snorkeling Fins Aren’t Too Stiff For You!
Now that you know how the foot pocket should feel, the next thing you should consider is how stiff the fin’s blade is. A blade that’s too stiff will give you foot and leg cramps in short order, regardless of how perfectly they fit you! Usually, this will happen if you choose fins that are longer than necessary for snorkeling.
If you want to know more about blade stiffness and length, you can check out these posts:
Short or Long Fins for Snorkeling: Which is Best?
Ideal Snorkeling Fins for Beginners (Recommended Brands and Models)
How Do Swim Fins Work? The Physics of Finning!
Disclaimer: Some of the links used in this article are affiliate links. That means I may get a small commission if you buy a product after following the link. If this article helped you, consider it like giving me a little thank you!
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