If you were asked to picture a pair of fins, the image you’ll likely conjure up in your mind is a pair of paddle fins. These “regular” fins are also known as blade fins, paddle fins or full fins.

However, in recent years there has been a new blade design that has become more popular: the split fin. As the name suggests, split fins have a split down the middle which is designed to mimic the shape of whales and dolphin fins.

Historically, paddle fins were the only fins available, so both beginners and pros alike had to use them. Now, an argument is being made that for beginners, split fins may be the better option because they are easier to kick with.

In this article, we will be discussing the pros and cons of using split fins vs blade fins, and why you might prefer one over the other.

Similarities

First, let’s start this discussion off with the ways in which they are similar, just so we are clear that there is not that big of a departure between these two fin designs.

If you really think about it, the only difference is that split down the middle. That split changes how the fins work mechanically (the only major difference), but pretty much everything else is the same.

For starters, if you have a preference for open heel or closed heel designs, don’t worry; both split fins and paddle fins offer both heel types.

Next, the other factors that you’d want to consider such as the price, weight, stiffness, etc., are all about the same whether you are going for a split fin or blade fin.

Differences

If so much is the same between these two types of designs, then what’s different about it? What exactly does having a split down the middle do?

The argument in favor of wearing split fins is that they are much easier to kick with. Some divers and snorkelers struggle to use paddle fins which can be hard to kick with.

Split fins have a split in the middle that allows some water to pass through and they are generally less stiff which makes kicking smoother (we’ll go more in-depth about the exact mechanics in another section).

The advantage of easier kicks is that it helps the diver or snorkeler conserve energy if they have weaker leg muscles. It also helps you psychologically when you feel that each kick is much smoother. However, since split fins are not stiff enough, it cannot generate as much power as paddle/blade fins.

As for blade fins, each kick is harder to perform, but each kick will generate much more thrust than a split fin can due to its stiffer blade and no split down the middle.

Blade fins are also great for propulsion efficiency, power, and air conservation assuming you have the leg strength to kick with them.

What do we mean by this? Well, the propulsion power of a paddle fin is a function of the strength of the kick. Said another way, the harder a diver kicks with a paddle fin, the more propulsion is generated. This allows experienced divers to adjust the strokes to attain a higher level of control.

To summarize this section:

• Split fins are good for beginners to use in calm waters because they offer decent propulsion and are easier to kick with . However, they are not ideal for stronger currents because they cannot generate enough thrust.
• Paddle fins offer better propulsion and control, however due to how stiff they are, beginners may find them hard to kick with. Experienced divers and snorkelers say that they have more control when kicking with paddle fins.

In the next sections, we will cover each fin type in more detail so you can better decide which one is better suited for you.

Overview of split fins

Split fins are easy to identify because they are the only ones that have a split down the middle. As mentioned, this was inspired by the split in the fins of whales and dolphins.

The theory is that the split can help to create a vortex in the water, which assists with propulsion and increases your speed.

Another advantage of the split is that on an upward stroke, water can easily pass through it. This is ideal because the upward stroke provides the least propulsion power, so in a blade fin it is costing a lot more energy and not providing much movement.

This is the reason why split fins are much easier to kick with and helps you conserve energy with each kick. It also helps that split fins are not as stiff, so they do not create as much resistance against the water.

That said, this strength is also the split fins’ weakness. Since it is flimsier, it does not provide as much thrust per kick. Even if you have powerful leg muscles, you will feel that your strong kicks are simply not providing you enough thrust relative to the strength you put into the kick.

Furthermore, split fins are also not ideal for some kicking styles such as the frog kick, nor are they good at backing up due to the lack of stiffness in the design.

For these reasons, split fins have an ideal group they can be used by: beginners and those with weak leg muscles.

Split fins are fantastic to learn on. Use them as a stepping stone to give you the confidence you need when you first start learning a water sport. They can help you develop your leg muscles, or help those with knee or hip issues work around their pain.

Since they are easier to kick with, split fins let you practice the correct kicking motion even if you don’t have strong leg muscles.

Overview of blade fins

Blade fins are what most people consider to be the “regular” fins. They are referred to by many names: blade fins, paddle fins, full fins, and so on.

They do not have a split down the middle and are much stiffer than split fins. You can find paddle fins in every single dive shop, but not necessarily split fins.

Since the blade is stiffer, it gives you the most powerful stroke. With split fins or when kicking without fins, even if you have strong leg muscles with a powerful kick, it can feel like you’re not generating the full amount of thrust.

With blade fins on, you can maximize the thrust generated per kick. Thus, they are great for experienced divers and snorkelers who want more control over how much thrust they can generate.

Full fins have a proven track record, being the original fin type that has been in use for decades. This type of fin design is used in practically every sport that uses fins; from snorkeling, scuba diving, to freediving and swimming.

Since you can generate the most thrust with a blade fin, they are the ideal option for scuba divers wearing bulky scuba gear and people who will swim against the strongest currents. Split fins will struggle to generate enough propulsion in these tough situations.

Furthermore, paddle fins provide exceptional maneuverability, provided you have the technique. They let you have greater control over every aspect of diving: angle, pitch, direction, and so on. You can easily swim forwards or backwards, spin around in place, and handle strong currents.

The primary downside of blade fins is that they can be difficult for beginners or for those with weak leg muscles. Due to how stiff they are, they can be hard to kick with since there will be enormous water resistance.

However, if you take the time to perfect kicking with paddle fins, you can attain more control and propulsion than kicking with split fins.

Which fin is right for me?

Unfortunately, there is no correct answer because everybody’s situation is different. We mentioned that split fins are ideal for beginners and paddle fins are better for veterans, but the truth is you can be experienced and still use split fins, or a beginner and use paddle fins.

Split fins are great when used leisurely because of how easy they are to kick with. You might also have an injury that you are working around which prevents you from using the much stiffer blade fin, so split fins are a viable option.

On the other hand, you may be a beginner that is ready to tackle any challenge. Even if starting out with paddle fins is more difficult, if you know that it’s what all the pros use, then why waste time learning to kick with another fin type? Let’s just get right into it.

With that said, if you simply do not have the leg strength to efficiently kick with a paddle fin, then you may have no choice but to wear split fins to start with. You can think of split fins as a stepping stone; something that will build you up to the next level.

If you have kids that are just starting out and they do not yet have strong leg muscles, then you can start them off with split fins.

Since split fins and paddle fins are similar in many respects, such as in price, heel types offered, weight, and so on, the biggest difference is in how they affect the way you kick. That is often the biggest factor – how you prefer to swim and how much thrust you need to generate.

Depending on your skill level, what kind of water you will be swimming in, and your leg strength, you can pick the fin type that is most suitable for you.

Whether you’re swimming, snorkeling, freediving, or scuba diving, you will be able to do it more easily thanks to the fins you’re wearing.

You may not necessarily need fins (scuba divers excepted), but they help you propel yourself through the water quickly while conserving more of your energy.

One question that is often asked is: how much faster can you swim with flippers on? With fins on, will you glide through the water as easily as fish do? Or is it only a minor difference, and if so, is it even worth it to wear fins?

Most swimmers would estimate that their swimming speed increases by 30-40% while wearing fins. However, this is highly variable depending on the type of fins you’re wearing as well as your kicking style. That said, it’s basically a forgone conclusion that you will improve your speeds while conserving your energy, which is why fins are such a useful piece of equipment.

In this article, we will go over how exactly fins can help you improve your swimming speed, what types of fins there are and how they benefit your swimming style, and why you should wear fins while swimming.

How do fins improve your swimming speed?

Helps you generate propulsion

In order to answer this question, we need to first discuss the mechanics behind how fins work. Fins, or flippers, were inspired by the webbed feet of frogs and ducks.

Various aquatic creatures have webbed feet to help them propel themselves more easily through water, and we land dwelling humans don’t, so naturally we are not very fast swimmers.

To give ourselves a similar benefit to having webbed feet, fins were invented to increase the surface area and flexibility of our feet to improve propulsion.

Now you may be asking, how exactly do webbed feet help improve swimming speed? Keep in mind Newton’s Third Law which states that any force is met with an equal and opposite force.

Each time we kick or push against the water, the water pushes back. By increasing our feet’s surface area (by wearing fins), this amplifies the force we generate and therefore we receive an equally powerful force back from the water pushing us in the opposite direction, thereby generating thrust. This ultimately leads to us swimming faster.

Without fins, even though you may have very strong legs, your feet don’t have much surface area and your kicks will slice through the water with little propulsion generated.

Improves speed even when not wearing them

There has been a plethora of research looking into the performance benefits of fins in the sport of Olympic swimming.

You may not know this, but many Olympic swimmers train with swim fins on (even though competitions don’t allow them) because it can improve their ankle and leg strength. They’ve found that training with fins can benefit swimmers even when not wearing them.

In these studies, a number of interesting discoveries were made. First, while the exact increase can vary, fins tended to increase most swimmers’ speed by 30-40%.

Furthermore, wearing fins drastically reduces the frequency of kicks. This is because each kick, having greater surface area, propels the swimmer faster and farther than without fins. For most swimmers, their kicking frequency decreased by about 40%.

Lastly, since they are kicking less, most swimmers also conserve more energy, estimated to be about a 40% decrease in energy expenditure.

Of note, the groups that benefit the most from these studies’ findings are probably scuba divers and freedivers, where the goal is not necessarily speed but how to decrease energy expenditure and conserve air.

Which fins are the fastest?

There are many different types of fins, and some fins are specially designed for their sport. For instance, freediving fins are not necessarily the best option for swimmers to use, nor are swim fins a good idea for scuba diving, and so on.

In this section, we will discuss the various types of fins broadly to give you an idea of their pros and cons. To be clear, we are not discussing brands, but characteristics of each type of fin.

To start off, you probably know about long fins and short fins. Of these two types of fins, which is the faster type?

Based on what we said in regards to surface area and propulsion, you might think longer fins are faster because they have significantly more surface area. However, that’s only taking into account the thrust of each kick, not the frequency.

Due to their length, long fins take much longer to complete a kick cycle than short fins. Short fins allow one to kick much more rapidly while still increasing the thrust of each kick relative to someone without fins. As a result, the combination of frequency of kicks and additional thrust tends to make short fins the faster option.

Where long fins excel is in energy conservation. It may not seem intuitive since each kick with long fins feels harder to do. However, the amount of thrust generated per kick and the low frequency of kicks to cover the same distance as short fins means that it’s energy efficient.

Hence, you will notice scuba divers and freedivers prefer longer fins because they are both sports in which energy conservation is crucial. On the other hand, swimmers and snorkelers tend to prefer short fins for the raw speed it can provide.

Lastly, a newer fin type is the split fin (most fins are paddle fins). Split fins have a partial split in the middle of the fin to mimic a fish’s tail. Many people report that they feel faster swimming with split fins because it feels effortlessly to kick with them.

However, split fins do not improve speed by much because if you feel like your kicks are too easy, then you are probably not generating much thrust and therefore your top speed isn’t going to be that fast.

Benefits to swimming with fins

Improve your kicking technique

Olympic swimmers often train with swim fins on even though they are not allowed to wear fins during competition.

The frequency and power of their kicks is often the limiting factor for swimmers, and they find that training with fins can help them improve their kicks.

Since the best way to kick with swim fins is to perform rapid, short kicks instead of big and powerful ones, they are training the exact areas they need to improve.

With flippers, not only will swimmers strengthen their leg muscles, but they reinforce the movement patterns they need to do.

Thus, even after they remove the fins, they will have improved their swimming performance overall by being stronger, faster, and more consistent with their kicking motions.

As for swimming with long fins, such as freediving or scuba diving, you will need to perform slow and powerful kicks. The purpose here is not speed, but energy conservation by traveling the greatest distance with the least amount of energy.

Give your shoulders some rest

Even though swimming is a low-impact sport, one area of your body that will take a beating is in your shoulders.

Shoulder injuries are the most common type of injury for swimmers and it can end their careers. If they have not learned how to properly perform their swimming strokes, then over months and years, they can hurt their shoulders.

Maybe you are recovering from an injury or just want to give your shoulders some time to rest, but you don’t want to stop swimming. In that case, fins can give you the boost you need to train with mostly your legs so that your shoulders don’t get aggravated.

Swim faster and farther

At this point, it’s no secret that wearing fins gives you a boost in your swimming performance, otherwise nobody would be wearing them.

By increasing the surface area of your feet, you can generate more thrust as explained by Newton’s Third Law.

One difference that initially throws a lot of people off when they wear fins initially is that it seems to be harder to kick.

That’s because the increased surface area of your kicks will be met with greater water resistance. Each kick you make with fins on will use more energy than usual.

However, each kick you make will also generate more thrust than usual, propelling you through the water faster and farther for the energy you spent compared to without fins.

So initially, you may struggle to swim with fins as your muscles may not be used to working so hard to overcome the water resistance.

That said, once you have gotten used to it, you will notice a significant improvement to your speed, distance traveled, and a decrease in overall energy spent.

Between the fin types, short fins will help you achieve faster speeds than long fins. While long fins have a larger surface area, meaning it should help you generate more thrust, they are also heavier which means it takes longer for your legs to complete a kick.

On the other hand, short fins have less surface area but are significantly lighter for it. They allow you to complete faster, smaller kicks that generate less thrust but, due to the frequency of your kicks, help you achieve greater speeds.

That said, long fins have the advantage over a longer distance. Short fins are faster for short bursts, whereas long fins can help you reduce overall energy output by propelling you further with each kick.

Swimming with fins vs. without

Now that you know about some of the benefits of swimming with fins, you can find many practical applications for fins:

• To train for competitive swimming.
• To cover a larger distance when snorkeling, open water swimming, spearfishing, scuba diving, etc.
• To overcome rough currents.
• For overcoming the water resistance when carrying lots of heavy equipment while scuba diving.
• To allow you to dive even deeper while freediving by assisting with the ascent.
• Gives you extra buoyancy to stay afloat while swimming or snorkeling.

And so on. These are just some of the most popular examples of what you can do, and I’m sure there are more applications than even this.

That said, do you have to wear fins? No, of course not. With the exception of scuba diving, where you need to carry around plenty of heavy and bulky equipment, I would say you don’t need fins at all.

However, if you like the underwater world then wearing fins is a no-brainer. They provide many advantages, are relatively affordable, and can help you enjoy the sport and keep you safe.

Downsides to wearing fins

In the interest of full disclosure, we need to discuss some downsides to wearing fins. After all, nothing is perfect, and even something that offers plenty of advantages has some pitfalls you need to watch out for.

For starters, it can be really awkward to walk on land with fins on. Particularly with long fins, the extreme length of the fin makes it a tripping hazard. You will either need to walk backwards into the water with fins on or wear your fins in the water so as not to trip on them.

Next, fins can rub painfully against your skin. There are open-heel fins and closed heel fins. An open-heel feel requires you to wear neoprene water socks to protect your feet which are an added cost. A problem that fins have is that they can rub painfully against your heels, giving you blisters.

Furthermore, if you are not used to wearing fins, you may not realize that your feet are about an extra foot longer than what you’re used to. You need to think of fins as extensions of your feet. If you don’t, you’re going to end up kicking and breaking coral reefs, and damaging your fins in the process.

Parting words

By increasing the surface area of our feet, fins can help propel us through the water up to 40% faster.

That said, the main purpose of wearing fins is not for speed, but rather for efficiency. For instance, in scuba diving, fins are mandatory to help divers lug around all of their heavy and bulky scuba equipment while conserving energy.

They are also extremely beneficial for freedivers and spearos that also need to conserve their energy so that they can stay underwater for longer.

As for swimmers wearing fins, it can help them train their leg muscles and perfect their kicking technique. Even after taking off the fins, they notice an improvement in their speed and technique.

Between short fins and long fins, short fins are faster in short bursts. They allow you to generate more thrust while still letting you kick relatively quickly, whereas long fins take longer to perform a kick cycle. Split fins feel easier to kick with but do not give you much top speed.

Whether you’re snorkeling, scuba diving, or swimming, fins can offer you many advantages. They’re quite affordable as well, so if you love the underwater world, you should definitely consider getting a pair or two.