One collision can change the future for a young swimmer
Head injuries can take you out for the meet...or out for the season.
Know your risk zones
Head-To-Wall Collisions
As swimmers get stronger and faster they need sharper timing at the 5-meter flags. A single miscount can mean a painful head hit and shaken confidence—or worse, a concussion.
Practice Lane Collisions
Mid-lane head collisions occur in traffic jams and circle swimming gone bad in practice.
Meet Warm-Up
Warm-ups often turn chaotic with dozens of swimmers crammed into lanes while coaches and officials are tied up in meetings.
Accumulated Impacts
Repeated, untreated small hits can cause mild traumatic brain injury or contribute to delayed concussion symptoms.
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Looks and Performs Like A Dome Racing Cap
Wear Under Your Team Cap
In stock
How do I measure for the right Hammer Head size?
It’s easy. Just measure the circumference of the head about 1 inch above the ears — that’s the sweet spot for an accurate fit.
For racing or a more compressed feel, wear your team cap over your Hammer Head and goggles. This gives you our signature smooth, wrinkle-free dome for maximum speed and hydrodynamics.
For the best comfort and performance, wear your Hammer Head with the logo centered in front. That’s how the cap is engineered to fit just right.
Hammer Head underwent drop testing by ACT Labs, the global consumer product testing lab, and was proven to reduce impact force by more than 50% compared to silicone and dome caps — making it the safest cap in the water.
But we didn’t stop at safety.
Olympic legend and performance expert Dr. Gary Hall, Sr. tested Hammer Head for drag reduction and found it to be up to 10.5% faster than traditional wrinkled silicone or latex caps. That’s the power of our wrinkle-free Honeycomb Impact Technology.
We strongly recommend wearing it in practice, meet warm-ups, and competition — because protection and performance belong in every lap.
As parents, we invest in the things that help keep our children safe and confident. While traditional swim caps are inexpensive and designed to be replaced when they wear out, Hammer Head® was engineered to do much more. It combines patented head-impact protection, premium durability, and competition-ready performance into one swim cap that's built to last.
With a 365-Day No-Tear Guarantee, it's more than a swim cap—it's an investment in your swimmer's confidence, comfort, and peace of mind every time they dive into the water.
For the best fit and protection, wear your Hammer Head® with the logo in front.
If you have long hair, make a low ponytail and tuck your hair completely inside the back of the cap before adjusting it for a smooth, comfortable fit.
Hammer Head® can be worn by itself or under your team or race cap during competitions, giving you the added confidence of head-impact protection while meeting your team's look.
How do I care for my Hammer Head?
After each swim, simply rinse your Hammer Head and turn it inside out to dry completely.
Avoid contact with sharp objects that could puncture the cap — treat it well, and it will deliver long-lasting performance.
Size Chart
Find your perfect Hammer Head Swim Cap fit with our sizing guide and enjoy comfortable, secure head protection in every swim.
Hammer Head Swim Cap
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Case Study
Brooke's Injury Story
Miscounts in the backstroke lead to concussion
Hear What Our Fans Have To Say
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Chris DahowskiHead Coach, Paseo Aquatics
"Because accidental head hits happen so often in the pool, we now require all our Junior-level athletes to wear Hammer Head swim caps in practice and at meets. The safety-first message truly resonates with our swim parents and reinforces our commitment to athlete well-being."
Jill GageSwim Mom, Proud Hammer Head Customer
"My daughter Sierra suffered a concussion during the 50-yard backstroke after misjudging her stroke count. She was out of the pool for over a month. While searching for a way to keep her safe, I discovered Hammer Head and immediately shared it with her coach. Now, she never swims without it. Don’t wait until it’s too late—protect your swimmer today!"
Rowdy Gaines3x Olympic Gold Medalist & Voice of USA Swimming
"Hammer Head is a simple yet essential piece of equipment for every swimmer. Let’s be real—head hits happen every day, above and below the surface. For the first time ever, Hammer Head combines 50% greater head protection, up to 10.5% more speed, and unmatched durability that outlasts any other cap."
Gary Hall, Sr.3x Olympian & Founder of The Race Club
"In a drag study test, we found that swimmers wearing Hammer Head’s innovative design at top race speeds experienced up to a 10.5% reduction in passive drag compared to traditional silicone caps. In a 50-meter freestyle, that can mean shaving tenths of a second — the difference between winning and losing."
"Safety is everything in our sport—emotional, mental, and physical. That’s why I’m proud to partner with Hammer Head, a brand that truly shares those values. You’ve got to check them out! Hammer Head is the safest, fastest, most comfortable, and longest-lasting swim cap in the world."
Customer Reviews
Overall rating: 4.8 / 5 from 79 reviews.
Just happened across this product when looking for a better option to cover my hair when wearing a dive mask in the ocean.. I chose to take a closer look because of the bright pink option. I was pleased when I discovered it had a head protector built in. I'm quite clumsy having bumped my head on coral when scuba diving and snorkeling. I've also made the mistake of bumping my head on the bottom of the boat. I've been testing it out in the keys this week. So far I'm super happy. It doesn't pull my hair out, it doesn't slide off easily either, it seems super durable as I'm constantly getting in and out of the ocean and I don't feel like I'm going to push my fingers through the rubber and of course it ties my dive gear all together with the pink.
I won this cap at NVSL all-stars 2022. It is so comfortable on my head and is my favorite cap. I always use it when I compete backstroke. This cap is awesome!!
Store owner replied:
Hi Abigail,
Thank you for sharing your great experience with Hammer Head! Let me know if you want to join our Affiliate Program. You get cold hard cash when you tell others about Hammer Head and they make a purchase. Super easy and 100% automated when you join. The link is on the top menu bar on our website: www.hammerheadswimcaps.com Cheers!
I like the snug on this cap. It better then the first one I got it the right size the blue on and hoping to get me more hammerhead shark swim caps
Store owner replied:
Thank you for sharing your great experience with your Hammer Head! Glad you got the right size. Let me know if you would might be interested in being an Affiliate. You can earn money making a Hammer Head recommendation that turns into sales. The link is on the top menu bar on our website: www.hammerheadswimcaps.com Cheers!
It looks like a very well-made swim cap. My only issue is that there’s no safety protection on the sides, which is where my daughter got hit in the head and got her concussion when she was in synchro swimming.
Store owner replied:
Hi Michael,
We're very sorry to hear that you're disappointed with Hammer Head. Your comment concerns us, and we'd appreciate the opportunity to better understand your experience. Please contact us directly so we can listen to your concerns and address them appropriately. Your feedback matters to us.
I am a 79 year old Master Swimmer and I wear my hammerhead for workouts and event swims. I value the added safety of the head protection for those rare occasions when I do hit the wall but I also value the comfort, durability, and smoothness of the no-wrinkle denser material.
I’m a senior Masters swimmer and compete in unfamiliar pools and events. While I love the comfort of the fit and heavier duty material that prevents wrinkling, I wear them primarily for the security of the padding.
Just brilliant! After my son suffered a concussion during training, having this hat makes him feel much more confident to return. Thank you Hammerhead!
Fits like a glove, and doesn’t work its way up while swimming. I actually feel some reduction in drag while wearing this cap! Thanks to “The Fundamentals of Fast Swimming” (Gary Hall, et al) for suggesting donning this cap for drag reduction!!
I've been swimming a few times per week with the same padded cap I purchased from you in Feb of 2024! Amazing durability. The one I recently ordered is just to hold in reserve, since at some point everything gives way (silicone can just hugely rip all of a sudden). But the first one I bought is still going strong!
I was a bit hesitant at first to try this. I was afraid I'd come across looking like one of the Eggheads from SNL. But after I put it on, it fit so perfectly, and I started noticing how poorly fitted other swimmer's caps were on their heads. Once I found out that I also got a slight speed bump due to reduced parasitic drag, I was all in.
Love, love , love your swim cap! You made a believer out of me!
Store owner replied:
Hi Ari, are you a triathlete, open water swimmer, masters swimmer? We'd love to know where you wear your Hammer Head.
at first, I was a little concerned I'd end up looking like a character from Saturday Night Live i.e. an egghead due to the honeycomb portion on the interior of the cap. But the cap fits perfect, and I don't have to worry about wrinkles along the top, causing parasitic drag.
We now have more than a dozen kids in Hammerhead Caps and we are adding more each week. The message of safety first, speed second is resonating with our swim parents.
My daughter Sierra sustained a bad concussion while swimming the 50 yard backstroke in a meet in October. She was unable to warmup in a pool with flags to get her stroke count down and plowed into the wall at a high rate of speed. That led to her being out of swim for over a month. As a mom, I was ready to start inventing something to protect her head if no one else had done it. While searching for my invention idea, I came across the hammerhead swim cap and I shared it with her Head Coach from Lifetime immediately. I won’t let my daughter swim without it! Every swimmer should have one period. More needs to happen to prevent concussions in swimming. Don’t wait until you are with your kid in the back of an ambulance to do something. Order the cap and spread the word about Hammerhead Swim Caps!
Store owner replied:
Hi Jill,
Thank you so much for your review and sharing your story. Unfortunately, these injuries are far too common. I'd love to invite you and your coach to my next roundtable meeting on 2/26 at 10AM CST focused on reducing head injuries and concussions in swimming. please email me at info@hammerheadswimcaps.com if you are interested.
My Best,
Theresa, Co-Founder and CEO
I love that it helps protect my daughter’s head when she swims!
I bought it for my kid to protect against concussions from hitting the wall on backstroke or collisions with other swimmers during practice. This is the only product I’m aware that provides some decent protection and for that reason he wears it. However, as a general swim cap it’s not that great. Unlike a regular cap it tends to want to want to slowly slide off his head. It also allows a lot of water in so his hair is soaked by the end of practice – it just isn’t very tight around the edges. So as a functional swim cap I’d give it one star because basically any swim cap out there will perform much better. But from a safety standpoint I give it five stars because, well, there’s nothing else that offers any protection.
Store owner replied:
Hi Christopher,
Thank you so much for your review. I think you may have the wrong size Hammer Head for your swimmer because it should not be slipping off your swimmer's head. If you shoot me an email at info@hammerheadswimcaps.com we can resolve this issue?
My Best,
Theresa, Co-Founder & CEO
Oh my gosh, where do I start. I am a 68 year old female who loves to swim. The problem was none of the caps fit my head. I bought two from Speedo. Too tight. I was about to give up when I read about your brand. My head is 22 1/2 around. Well, it fits perfect, keeps my head and ears warm and itvis easier to swim on my back as well. I love it!! Thank you so much! You are saving my hair!
Great product. My son feels more confident when diving off the starting block and speeding into the wall for a flip turn knowing that his head is protected by the hammerhead cap.
We at Paseo Aquatics cannot thank Hammerhead Caps enough. We like to know that we are taking the necessary steps to putting the safety of our athletes first. It brings peace of mind.
Tested by independent lab, ACT, and found to be 50% safer than silicone and latex swim caps.
Tested by Dr. Gary Hall, Sr. and The Race Club and found to mirror the performance of a dome cap, which is up to 10.5% faster than all other swim caps.
Nominated Product of the Year by WOWSA and endorsed by Sensory Friendly Solutions for its protective, sensory-friendly design and fit.
