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Water polo is officially a “non-helmeted contact sport,” yet head impacts are routine, expected, and often underreported—especially repetitive ones.

Water polo is one of the most physical aquatic sports in the world. Elbows fly, bodies collide, and contact happens above and below the water — often out of the referee’s sight. Yet while players wear caps to protect their ears, the skull itself is left almost completely unprotected. If you’re a water polo athlete, parent, or coach, the question isn’t if head contact happens — it’s how often. That’s why more players are choosing to wear Hammer Head under a regulation water polo cap: to add meaningful head protection without changing how the game is played.

Your sport demands contact, precision, and protection

Know Your Risk Zones

Adult offensive center water polo player is preparing for a powerful ball strike in a swimming pool with a black background. Hammerhead swimming cap is worn under his white water polo swim cap as a comfortable and protective competition helmet.

Offensive Center - 2 Zone

Holds position against defenders and is exposed to elbows, ball strikes, and is jostling for position, experiencing a 37% of all recorded head hits.

Female water polo players are in action with a yellow ball near a net. This image shows how aggressive players are in the swimming pool. the Hammer Head swimcap is worn under their practice and competition water polo caps for extra head protection to minimize concussions when ball strikes or elbow strikes to the head happen. This will help protect your athletes head.

Left Offensive Side of the Pool

Right-handed players attack from the left side, so that zone sees higher shot-volume and physical contact.

Adult male water polo goalie is in action with a ball heading right for his head in a swimming pool. He has a Hammer Head swimcap under his water polo cap for extra head protection to avoid or minimize head injuries.

Goal Keeper

Vulnerable to direct shots, blocking efforts, and collisions with offensive players crossing the goal line.

Submerged Sruggle Zones

These impact zones include battles for position, wing lifts, steals, and scrambles near the 5-meter line.

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Hammer Head Swim Cap

$34.95 USD

Free Standard Shipping on all Domestic Orders over $50!

1-Year No-Tear Guarantee
It Won't Slow You Down
Looks Like A Dome Racing Cap
Wear With Your Team Cap

Choose Your Color Black

Choose Your Cap Size Small - 19″ to 20.5″ heads

Small - 19″ to 20.5″ heads
Medium - 20.5″ to 21.5″ heads
Large - 22″ and larger heads

Product variants

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.

For aquatic athletes with long hair, be sure to make a low ponytail in the back and tuck your hair up inside the back of your Hammer Head swim cap.

Hammer Head is designed to look sleek, smooth, and streamlined in the water. The protective honeycomb layer is hidden inside, so all you’ll see on the outside is a clean, wrinkle-free dome — not a bulky helmet.

It fits just like a high-performance swim cap, only better:
No wrinkles that slow you down
No bulky shape or awkward profile
A smooth, hydrodynamic silhouette that looks fast and feels even faster

Most water polo players say it’s the best-looking cap they’ve ever worn — and the most confidence-boosting.

Protection you can’t see. Performance you can feel.

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.

Why does Hammer Head® cost more than a traditional silicone or latex cap?

Because it’s engineered to do more — and last far longer.

Most silicone caps cost $10–$15, but swimmers typically burn through 4–5 per year, spending $40–$75 annually on caps that tear, stretch, or wear out.

Hammer Head is $34.95 and built to last years, not months. That makes it the smarter long-term value and the only cap that delivers four game-changing benefits:

Head Safety, Speed, Comfort and Durability!

Aquatic sports have embraced innovation in tech suits, goggles, training gear, and nutrition. It’s time we all expect more from a swim cap — and Hammer Head is the next evolution.

The Hammer Head logo always goes in the front and the cap size is labeled on the inside back of the cap.

Hammer Head is built to work quietly behind the scenes while your team and sponsors shine out front. Just slip your Hammer Head on first, then layer your team cap over the top for practice or competition.

The result?
A perfectly smooth, wrinkle-free racing surface
Better body position and hydrodynamics

More confidence to train and race aggressively

You get all the safety and performance benefits — while your team logo gets the spotlight.

For team orders contact us at info@hammerheadswimcaps.com

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.

Want A Bunch For Your Team?

For a custom quote and quantity discount information with or without your team logo CONTACT US NOW.

Many coaches are requiring their 10&U swimmers to wear Hammer Head swim caps by including it in their registration kit.

Email us at: info@hammerheadswimcaps.com
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Yes. Hammer Head’s patented, multi-layered design naturally offers more insulation than thin silicone or latex caps. The thicker top layer and protective honeycomb structure help retain heat, making it a great choice for swimmers training in cold pools, open water, or early-morning practices.

While Hammer Head isn’t designed as a thermal cap, many athletes tell us they feel noticeably warmer and more comfortable in cooler conditions — without extra bulk and without affecting speed or stroke mechanics.

Warmth, comfort, and protection — all in one cap!

Injury statistics graphic showing that water polo goalie have a 47% risk for head injury, that 36% of water polo players on average suffer from 2 or more concussions in practice and competition, how centers and strikers have a 23% higher risk of concussion because of aggressively play in their positions and how women suffer a 13% higher risk than men playing water polo - all on a red background with white text and labels.

Water polo player in action wearing a red Hammer Head swim cap under her regulation cap with a ball about to hit her head. This is on a red border and text about head injuries.

Trust the Research

Revolutionary Concussion Research

A well published study conducted by UC Irvine tracks the perils of water polo head injuries. They et up a crash test dummy head and radar gun to measure the impact of balls thrown at different speeds.

3D rendering of a brain with a focus on the cerebellum area, highlighted in red.

Concussion Resources Team Up

USA Water Polo, the BIAA, USOPC, and other aquatic sports support TeachAids’ CRASHCourse developed with thousands of athletes to raise awareness on concussion causes, symptoms, and recovery insights.

Two men playing water polo in a pool with a yellow ball. They illustrate the contact sport and potential risk zones for head injury. It is important to know how to choose the right swim cap. Choose a swim cap with head protection and a swim cap for head safety.

Most Common Injuries

🚑 In college water polo, concussions = 11.4% of all injuries. The #1 injury diagnosis. Other injuries include facial (teeth, eye, skin), labrum tear (SLAP-lesion), rotator cuff injury, patellofemoral pain syndrome and back pain.

Five people standing by a pool, holding yellow water polo balls, with a water polo goal and a swimming pool in the background.

With Skill Comes Concussions

Prevalence rises with competitive skill level raise with over one-third of water polo players reporting concussions in games or practice; High School: 31.8%, Masters clubs: 43.1% and NCAA 51.3%.