Silicone vs Plastic vs Fibreglass vs Carbon: Which Is Best for Freediving Fins?

Silicone vs Plastic vs Fibreglass vs Carbon: Which Is Best for Freediving Fins?

The first question most new freedivers ask after the first course is 'which fins should I actually buy'? There are 4 different blade materials to choose from; silicone, plastic, fibreglass and carbon. Of course, they all have pros and cons and are really designed  different purposes, budgets and types of diver. This guide is to help match you to your prefect fins. 

PLASTIC: THE BUDGET STARTER

Plastic (technopolymer) fins are what most freedivers buy first because they're cheap and widely available. Generally plastic is very stiff (inflexibile). This means it will drive you forward whatever you do, but unless you're already well trained they can teach some really poor kicking technique. They will also put a lot of strain on ankles and calves. If you're a beginner who hasn't built their leg muscles for finning yet, this means pain and cramps ever after a few dives. Plastic is also pretty tough but leave them in a hot car or against a hot surface and they'll warp permanently. For those of us aesthetically inclined, they will also fade from UV exposure and scratch easily.

So, if you're a beginner on a tight budget plastic may be the way to go. However, if you stick with freediving and improve (15m+ depth) you may find yourself quickly discarding those plastic fins for something better, wasting the money you thought you saved.

SILICONE: THE All-ROUNDER THAT ADAPTS TO YOU

Silicone is the latest innovation for diving fins. While a little more expensive than plastic short fins, they are much more versatile and will serve you well throughout your freediving journey. Broadly they appeal to two groups: beginner/intermediate divers who want to improve quickly and experienced divers who want fins that feel good but are easy to train and travel with. 

So, let's start with the feel. Silicone is much softer and more flexible that plastic. Full-silicone blades flex naturally with every kick training pointed toes, straight legs and the hip-driven kick technique that efficient freediving demands. In effect, these are short fins that feel like long carbon/fibreglass blades and prepare you for them in the future.

The softer material is also more gentle on ankles, calves and quads than plastic. If you're unusued to swimming with fins, silicone can really help to cut down on the ankle soreness and cramps that accompany your first long days in the water. 

If you plan to dive or snorkel on your next holiday, or go pool training straight from the office, long freediving fins and incredibly inconvenient. They need to be checked in airline luggage, and require specialist cases to avoid chips and cracks. Short silicone fins can fit easily inside a standard carry-on bag or backpack and, of course, they literally cannot crack or shatter! They are by far the most durable option. 

The one thing silicone won't do is out-perform a long carbon or fibreglass blade in a race for depth (although Alexey Molchanov did dive to 102m in silicone fins!), but that's not the goal. Silicone fins' job is to build the technique, comfort and durability that everything else depends on which is why so many freedivers use them not just to learn, but for years after.

FIBREGLASS: YOUR FIRST BIG PURCHASE

Step up to fibreglass long fins and you get a definite performance jump. Long fins move more water than short giving more power, and the blade snaps back fast with no "memory," giving you a smooth, responsive kick. The trade-off is that these will be more demanding and tiring to use than silicone short fins, but with a proper foundation in technique and conditioned leg/ankle muscles they can be a lot of fun. 

While certainly more durable than carbon, fibreglass is still fragile - one firm whack on a rock or boarding ladder and they will chip and crack. 

CARBON: ELITE-LEVEL PERFORMANCE AT A PRICE

Carbon fibre is as good as it gets for pure performance. It converts almost all of your leg's energy into thrust, weighs next to nothing, and saves precious oxygen on long descents — which is exactly why competitive freedivers rely on it. But that performance comes at a price, literally and physically. Carbon blades are brittle. A knock against a boat ladder can snap a blade that cost you hundreds. And honestly, if you're not regularly diving past 40m, you don't need it yet.

AT A GLANCE

QUESTIONS DIVERS ASK US ALL THE TIME

Are silicone fins actually good for freediving, or just for beginners? They're good at every stage. New divers use them to build technique. Experienced divers keep using them for travel, warm-up sessions and pool training to keep the feel of long blades.

Won't silicone fins slow me down? For sprinting or chasing depth records, yes, a long carbon blade will beat them. But that's not what silicone fins are for. They're built to teach your body the movement that makes every other fin work better.

Can I actually fit these in carry-on luggage? Yes. That's one of the biggest reasons divers adopt them. No fin bag, no oversized baggage fee, no worrying about a fragile blade getting cracked at check-in.

What fins should I buy after my first freediving course? Most instructors will tell you the same thing: start soft. A flexible fin like silicone creates good habits early, before you're tempted to muscle through a stiff blade with bad form. Buying cheap plastic is tempting, but if you throw them out it's really a false economy.

Do silicone fins irritate the skin? Not if they're made properly. Food-grade, hypoallergenic silicone is designed specifically to avoid the chafing and irritation common with cheaper rubber foot pockets.

There's no single fin that's "best" for everyone. Personally, we have two pairs: a long fibreglass/carbon for deep dives and competitions, and short silicone fins for travel, training and having fun.

Explore the DIVE SELKIE Freediving Fins — built to be the last short-blade fins you ever need.