Speedo fins are among the highest quality swim fins available. They’re also some of the most sought-after training tools. Because of their incredible ubiquity, I thought that a comparison of the two most popular Speedo swim training fins would be helpful for swimmers unsure of the difference. Knowing Speedo’s quality control and thorough attention to detail, there is no wrong choice. But hopefully this review will give you an idea of which suits you best.

Speedo Short Blade Fins

Speedo Short Blade Training Fins

The Speedo Short Blade fins incorporate a nice combination of resistance and propulsion to increase the efficacy of the training session. I have been putting the Speedo Short Blade Fins to work for several years now and I’m still pleased with how these fins hold up. Their compact design makes them ideal for technique training, while their short, rigid blade makes them perfect for maintaining kick tempo and overall speed, while fine-tuning ankle flexion and timing. The entire fin is made from soft, durable silicone. The silicone material remains stiff against the water, but soft against the foot – ideal for avoiding chafing and blisters.

These mighty little fins can even tackle the surf. Their modest size makes the Short Blades highly manoeuvrable in open water. Plus, their lightweight composition makes them an easy take-along companion for team practice, ocean swimming, or travel. And, although I’m typically not a fan of silicone fins because of chaffing, I found these to be quite wearable (though I’ve never worn them in salt water).

Speedo Biofuse Fins

Speedo Biofuse Fins

Just like the Short Blades, these fins provide boosts in power, strength, and speed when the fins come off. But, unlike the square toe of the Speedo Short Blade Fins, the Biofuse Training Fins feature a more rounded edge, as well as a notched blade. The notch in the tip of the blade stabilizes the fin laterally – ideal for swimmers with knee problems. And impressively, a few laps in the Speedo Biofuse Fins is enough to build intensity in your calves, thighs, and buttocks.

Rather than utilizing only soft silicone, the Biofuse melds both hard and soft materials to help maximize the fins’ performance and fit. The soft silicone on the foot pockets is fairly comfortable – though my heels felt a bit raw until the 4th or 5th wear. One note on Biofuse fins: It seems that they run a bit small. If you’re between sizes, you’ll probably might want to choose the size up.

The difference really comes down to preference and utilization. While both fins are considered a short blade training fin, the Speedo Biofuse Fins’ blades are slightly larger (about 15%) than the Short Blades. As a result, the Biofuse Fins demand a heavier workload by providing more resistance. However, if you aim to focus on tempo and technique, the Short Blade may be the better option.

Zoomers Fit Pair

Great For Conditioning

Made from durable, stiff rubber, the Finis Zoomers Fit Swim Fins can help you achieve your water-based fitness goals. Their hard, short blades use the patented Zoomers technology to work both your upper leg muscles and cardiovascular system. They were designed to easily generate forward propulsion, while still heavily engaging the quads, hamstrings, and glutes. Plus, short bladed fins help promote a faster, more compact kick that’s specific to swimming. Finis added a “Flex Box” on the underside of the fin to further strengthen muscle groups that other, traditional fins exclude. The “Flex Box” helps catch water during the up-kick of the flutter kick, and targets the back of the legs for a more effective, full leg workout. Finis Zoomers Fit Fins engage all of the muscles in the leg while providing an intense cardio workout.

High Quality Finis Brand Name

Finis puts a lot of time and research into designing each of their fin models to serve a specific purpose. The Zoomers Fit Swim Fin, with its unique blade shape, is a fitness-orientated fin aimed at fitness and competitive swimmers. In addition to their ability to raise strength and cardio levels, this Finis fin is also designed to help float the legs into proper body positioning. This slight buoyancy allows swimmers to achieve an ideal body position in order to better slice through the water with efficiency. The Zoomers Fit are made from durable, yet lightweight Surflex material that can withstand a serious workout and remain comfortable against the skin.

Extremely Comfortable

The Finis Zoomers Fit Swim Fins might make your leg muscles burn, but their comfort fit foot pocket is sure to remain soft against the skin. The fins utilize a close-heel design that ensures a chafe-free, slip-free fit. The Zoomers Fits are available in a wide range of foot sizes that can easily fit the majority of male and female swimmers. The fins are comfortable enough to wear for endurance workouts, yet effective enough to produce real results in just a few short swims.

Made by Aqua Sphere – a brand which targets triathletes and fitness swimmers – the Zip Fin (now the Zip VX Fin) performs like an athlete itself. It’s blade features an interesting, non-traditional design which allows for more intense lower body workouts without over-extending your ankles.

Aqua Sphere Zip VX FIns

The foot pockets are made from rubber which allows for the most comfortable fit. (I always prefer rubber foot pockets over silicone). Also, the heel on this fin is not enclosed. Instead, there is a comfortable, neoprene-covered, adjustable heel strap featuring pull tab adjustment buckles. The heel strap is also replaceable if it ever wears out.

One of the most unique features of the Aqua Sphere Zip Fin is its split bade design coupled with its “Nature’s Wing” technology. The fin actually functions more like a hydrodynamic sea creature’s fin rather than a traditional swim training fin. When you first start kicking with this fin, you can definitely feel the power behind the technology. The split blade seems to stabilize the fin in the water, keeping it from moving laterally and thus, reducing ankle fatigue. Aqua Sphere claims that a reduction in ankle strain will result in an ability to engage the entire leg and work out for far longer than would be possible in a more standard fin.

Just like the Speedo Optimus, it seems like the Zip Fin requires less power for a greater return. I’m not sure exactly how the system works, but the Aqua Sphere Zip Fin seems to flex naturally and fluidly in the water. Imagine a manatee’s flipper fluttering through the current. That’s exactly how this fin feels. Although the fin blade itself is made of plastic, there are rubber channels throughout which allow the blade to flex at multiple points – making it a very comfortable flutter kicking fin. The squareness of the blade disallows breaststroke kicking, but dolphin and flutter work beautifully.

The Zip Fin is available in sizes S-L.

One of the newest additions to the Speedo family is the Speedo Short Blade Fin.

The Short Blade fin by Speedo is a small, compact fin designed for the strength- and cardio-training needs of athletes. The Short Blade is made of 100% silicone for increased comfort and durability.

Speedo Short Blade Fins

The blade of the fin, which comes only about 3 inches off of the foot, is unique to this type of fin. The shortness of the blade is meant to allow for a faster, shorter kick (typical of the flutter kick). The fin construction is also designed to stabilize kicking tempo. However, because of the intense muscular workout these fins promote, they may tire a recreational-swimmer. (Remember, the shorter the fin, the harder and faster your kick will need to be; longer fins for diving require less tiresome kicking because of their length). Therefore, I would recommend these fins primarily to athletes or exercise gurus.

The fin was well-suited to the flutter kick and – unlike the Speedo Optimus – it seemed to adapt more smoothly to the breaststroke kick as well. Overall, the fins created a pretty decent amount of resistance, meaning that the Speedo Short Blade might make a good exercise or training fin – but you may want to stick to a basic flutter kick.

My only qualm with these fins is the material. Although many people prefer silicone to rubber because of its longevity and feel, I found that the silicone was rather abrasive on my heels. Perhaps this was a result of a higher fit on the ankle or the stiffness of the material, but I found the foot pocket to be somewhat uncomfortable.

Overall, the Speedo Short Blade Training Fins proved highly effective for their intended use (flutter kick improvement), but they fell short on comfort. For a similar, more comfortable fin, check out the Speedo Optimus Training Fin.

The Speedo Short Blade Fin comes in numerous sizes (XXS-XXL) based on shoe size. Regularly in stock at AquaGear Swim Shop.

Finis Zoomers Fit Swim Fins are made from a lightweight, comfortable material called surflex rubber. Surflex is a mixture of recycled and new rubber granules combined with high-tech resins. The surflex material makes this swim fin more rigid than a pure rubber or foam fin.

Finis Zoomers Fit Fins

While most traditional training fins are meant for swimmers focusing on training at race speeds or improving their stroke work, the Zoomers Fit is a fitness oriented swim fin, meant for swimmers looking for a more challenging cardiovascular workout. As soon as your foot starts moving you’ll notice the propulsion created on the up kick. This propulsion is created by a channel underneath the blade of the fin called the “flex box”. By creating resistance this “flex box” will not only help to target and strengthen the glutes and hamstrings of the swimmer, but will help to ensure a more intense cardiovascular workout. These fins are designed to make swimming easier while also increasing leg strength. Because of their buoyancy, the Finis Zoomers Fit Fins promote an elevated body position. This elevated position helps keep my legs active during the swim.

Like most traditional swim fins, the Zoomers Fit have a short blade. Due to the short blade design, shorter, faster, flutter kicks ideal for fitness swimming are possible. Faster flutter kicks translate into a more rigorous cardiovascular workout. See my section on Cardio on the main page of the Swim Fins 101 info site. When properly sized, the closed heel design of the Finis Zoomers Fit provides a secure fit ensuring a proper transfer of power from leg to fin. Remember, a tighter fitting fin is a more efficient fin. See my relevant section on Proper Fitting Fins on the main page of the Swim Fins 101 info site.

In summary, I would recommend these to a swimmer who wants to focus on getting a good cardiovascular workout while also targeting and strengthening the glutes and hamstrings. They would not be appropriate for a competition swimmer looking to train at race speeds.

By the makers of the popular Zoomers swim fins, Finis Positive Drive Fins are unique in that they are designed to be compatible with all strokes: freestyle, backstroke, breaststroke, and butterfly. Because of the short, ellipsoidal blades, the Positive Drive Fins are a very interesting additive to laps of any style.

Finis Positive Drive Fins

The Positive Drive Fins incorporate a unique asymmetrical blade design which correct the swimmer’s kick and encourage a natural “supination” kick. In other words, the fins maintain an inward rotation on the feet, allowing this natural kick cycle to generate increased propulsion. This was certainly true. The fins were light on resistance, but definitely gave a substantial boost to my flutter, breaststroke, and dolphin kick.

In fact, one of the most unique features of the Positive Drive Training Fins is their ability to be used safely with the breaststroke kick. Many traditionally-shaped fins catch improper resistance on a breaststroke kick, which could cause joint injury or discomfort. These fins, however, have a fantastic capacity to accommodate the breaststroke kick without the risk of injury. I was impressed by the power they added to my breaststroke, but my ankle flexion felt somewhat impeded by the cut of the fin.

Just as advertised, the short, elliptical blades are effective when used with freestyle, breaststroke, backstroke, and butterfly. And although these fins are economical and convenient, I thought the level of comfort was a bit lacking. The silicone did not yield to the contours of my foot, making the top arches of my feet a tad uncomfortable during my swim.

On the other hand, I give Finis high marks for the ingenious use of an adjustable heel strap rather than a traditional foot pocket. This feature holds the fins securely in place without the chaffing often caused by an ill-fitting heel. All in all, the Finis Positive Drive Fins are a valuable addition to any swimmer’s training equipment (especially if you’re an IM’er).

Positive Drive Fins come in a variety of sizes from XS-XXL based on shoe size.

UPDATE: As of 2013, these fins are no longer being made. Sorry, folks!

Speedo, long-regarded as a forerunner in aquatic fitness products, boasts some of the best swim fins on the market. The Speedo Optimus fin is a prime example of Speedo’s commitment to quality and effectiveness in all of their products. Made from natural rubber and designed with your feet in mind, the Optimus swim training fin is both highly durable and extremely ergonomic. Although my hamstrings, thighs, and glutes were burning by the end of my workout, my feet and ankles remained secure and unobstructed by the fins.

The Optimus swim fin features a unique blade design resembling a fish tail. This V-shaped blade allows for greater ease of motion in the water and thus, greater speed. The short, wide blade of the fin minimizes the amount of resistance required to move forward. Interestingly, it seems that the propulsion gained from the fins nearly outweighs the effort put into the kick.

In my own experience, the Speedo Optimus fins are made for swiftness. Seemingly, the blade design allows for greater amounts of water to pass through the center of the blade, while the longer sides produce greater resistance – allowing you to harness latent energy from the water with very little effort. In practice, this means that the Optimus fin provides for a smooth, easy kick, while simultaneously maximizing the return.

Likely designed for freestylers, this fin promotes proper kick and stroke tempo on the flutter kick. I found that the lengthened kick also encouraged full body rotation and an extended stroke overall. Essentially, the Optimus fin is an effective training aid for those swimming the front or back crawl; however, if you are a sideswimmer or a breaststroker, you may not find this fin to be as effective or as comfortable as it often catches resistance in the wrong direction.

Overall, I found the Speedo Optimus Swim Fin to be a powerful addition to the flutter kick. If you are going for a comfortable fin to boost your flutter kick performance, this fin will surely deliver.

These fins come in a variety of sizes (XXS-XXL) based on shoe size and seem to run exactly as sized.

Once again, Speedo hit the mark with their Biofuse Fins. These zippy, silicone fins are likely one of the best strength training fins on the market.

Speedo Biofuse Fins

The name “Biofuse” reflects Speedo’s melding of both soft and hard silicones into one cohesive design. Because of this unique use of materials, the Speedo Biofuse swim training fins fit the foot properly with no adjustment necessary. The Biofuse really lives up to its name in that it doesn’t feel foreign to wear. I found the foot pocket to be as comfortable as advertised without any slippage.

This fin was created specifically to maximize the wearer’s leg strength and kicking speed. As mentioned previously, the stiff, short blade encourages quick, short kicks in order to keep the legs afloat. As a result, proper kicking tempo is promoted and paired with proper arm technique.

Also, the stiffness of the blade makes for a more powerful stroke. Just as physics suggests, the stiffer blade requires more leg strength to move through the water; however, it also delivers more vigorous propulsion than many other fins, especially when used in conjunction with the flutter or butterfly kick. In other words, this fin will require a decent amount of work to use effectively, but the return on your kick more than doubles the efficiency of the stroke. Unfortunately, the Biofuse fins are not quite as efficient when it comes to the breaststroke. Although the rounded tips of the blade make it somewhat easier, they are simply not designed to handle such a kick.

I found this fin to be somewhat similar to the Speedo Optimus, save for the material. While the Optimus is made of all-natural rubber, the Biofuse is made from silicone. Although I have nothing against the durability or performance of silicone, I find it to be somewhat abrasive against my skin. For this reason, the Speedo Optimus still tops my list of favorite Speedo swim fins. Overall, the Biofuse training fin is highly versatile, well-fitting, and stylish.

This fin comes in a variety of sizes (XXS-XXL) based on shoe size.

Aqua Sphere Alpha Fins are unique in that they are constructed entirely of EVA foam. EVA is soft and pliable, and there’s a lot of flexibility to the fin when compared to traditional fins made of semi-hard rubbers or plastics.

Aqua Sphere Alpha Fins

The EVA foam makes Alpha Fins positively buoyant, which means they float when placed in the water, rather than sink like other plastic and certain rubber fins. The bottom of the Alpha Fin, near the opening where your toes sit, has two small holes in it to allow water to drain out easily. This is definitely a plus, since moisture left over in the foot pocket would otherwise grow mold. Allowing for water drainage as well as air flow is a simple design feature that helps these fins last much longer than fins constructed without such vents. The holes are small enough that they don’t have any effect on the resistance created by the fins, and you don’t notice the vents when swimming with them.

The physical design is also unique to this model of fin. Rather than a squared-off blade like most fins, the Alpha Fins feature a curved profile, that according to Aqua Sphere, the manufacturer, allows the swimmer to perform a breast stroke kick while wearing them. Normally, a whip kick is impossible or cumbersome with traditional flat blade fins, since traditional fins are meant for a flutter kick either slowly while scuba diving or a faster flutter for cardio and swim training. I found that these were “ok” at breast stroke, and somewhat awkward for flutter kick. I do know of people who swear by these though, so you’ll really need to try them out yourself and decide if you like them. (Make sure you rinse them off when you’re done swimming and don’t walk on the bottom and you won’t have a problem). See Caring For Your Fins on the main page for more on basic care to make your fins last longer.

The alpha fin features an open heel design, similar to a strap on fin, except the “strap” part is not detachable – it’s moulded onto the fin. You put your foot all the way into the foot pocket, and then pull the ‘strap’ up and over your heel. I found the fit to be very snug, and that’s important when choosing a fin. You want to get a good transfer of power from your leg to the fin (loose fitting fins are less efficient). Please see the Proper Fit section under Choosing the Right Fins for more on why this is the case.

To sum up, this is certainly a unique fin design and one that you’ll really need to try out yourself to determine how they’ll work for your swim routine.