If you’ve ever wondered whether you can swim with a certain pair of earbuds or headphones, the answer is usually no. Even the many that offer an IP68 rating aren’t meant for the more extreme pressures of swimming, and Bluetooth doesn’t travel through water very far. But some headphones are designed for swimming, and the H2O Audio Sonar are perhaps the best among them. With on-board storage and Bluetooth as options, these bone conduction headphones strap right onto your goggles and bring the jams along for even lengthy training sessions. They may be pretty niche, but if you’re searching for swimming headphones, these are probably just what you want.

Source: H2O Audio

H2O Audio Sonar

The H2O Audio Sonar are a killer gadget for swimming. They can store audio files locally or play over Bluetooth from a smartwatch as long as both are connected to your goggles while you swim. In the water they offer pumpy sound to get you in the workout mood while keeping your ears open to hear lap timers and your surroundings. They may not be good for much on land, but swimmers won’t find much better options than these.

Connectivity Technology

Bluetooth

Play Time

7 hours

Waterproof?

Yes

Brand

H2O Audio

Power Source

USB

Special Feature

Built-in 8GB MP3 player

Speaker Technology

Bone-Conduction

IP rating

IPX8 (up to 3 meters)

Music Source:

Bluetooth, MP3 player

Supported formats:

MP3, M4A

Weight:

40g

Color:

Blue and black

Pros

• Robust sound in water
• Waterproof to 3 meters
• Handy internal storage

Cons

• Need separate headband/goggles to wear
• Limited utility out of water
• Stiff buttons

Price and availability

The H2O Audio Sonar are listed on H2O Audio’s own website at $130, but they have been selling for $100 for years now, and Amazon lists their price as $100.

Design and fit

H2O Audio Sonar bone conduction headphones worn with swim goggles

The H2O Audio Sonar have a design unlike most headphones you will have encountered, fitting two fairly bulky, almost peanut-shaped, bone conduction drivers at either end of a blue tether. That tether is long and thoroughly flexible, allowing for a broad range of fits and head sizes. The main driver units offer controls with play and a Mode button on the right side and volume up and down on the left side. The buttons are a bit stiff to use.

Each driver unit has a cutaway channel designed specifically for you to slip the band of swim goggles through. This way, the band will keep the drivers pressed against your cheek bones so H2O Audio Sonar can work their bone conduction magic. The channels work best with flat bands, keeping them securely slotted, though thin, string-like bands will work as well and are unlikely to come out while wearing the headphones and goggles.

A downside to this design is that it’s effectively only wearable with swim goggles. If you think you’re going to get some use for these headphones out of the pool as well, you’re in for a letdown. You might be able to pull something off with a very low-profile headband or the right pair of glasses, but those solutions will likely end up in an imperfect alignment of the drivers and an uncomfortable fit for the glasses or headband.

H2O Audio Sonar bone conduction headphones attached to swim goggles

The headphones are made for swimming and have the appropriate waterproofing with an IPX8 rating and tolerance for submersion down to 12 feet — deeper than you’re likely to go while lap swimming. In my time swimming with the H2O Audio Sonar, they showed no issue with water even from the extra pressure of flip turns and fast open turns.

The back side of the right driver unit has a series of metal contacts for linking up with the pogo pins on the proprietary USB charging cable. The cable latches on magnetically to the headphones. Though the connection is stable enough for charging, data transfer is a bit more sensitive and really requires the headphones to be completely undisturbed.

Features

H2O Audio Sonar bone conduction headphones sitting out

The key feature of the H2O Audio Sonar is their design, allowing them to be used for swimming — something your everyday earbuds and headphones simply cannot do. While the headphones support Bluetooth, the more critical feature is the built-in 8GB of storage and MP3 player. Bluetooth can’t transmit more than a couple inches through water, so unless you’re playing audio from a waterproof smartwatch also attached to your goggles or tucked into a swim cap, you’re going to need that MP3 player.

The MP3 player supports M4A (iTunes) files as well. Once loaded up, it can play back your audio while you swim. Controlling it requires some taps, multi-taps and long-presses. This allows for track skipping, volume adjustment, fast forwarding and rewinding, or folder navigation if you load music to the headphones with a folder structure. Without a visual interface, it can be a little tricky to find exactly what you want to play at any given moment. If you don’t like repetition, the headphones conveniently resume playback where you left off when powered back on, so you won’t always be starting back at the beginning of the same playlist. Double-tapping the play/pause button will also enable a shuffle mode for random playback order.

Ultimately, the headphones are fairly simple, feature-wise, because their main job is to let you listen to something other than the sound of rushing water while you swim. That’s already one hell of a treat if you’ve already spent hundreds of hours wishing you could have any sort of distraction from the pool tiles passing below while you get your workout in.

Performance and audio quality

H2O Audio Sonar bone conduction headphones sitting above an ear

The H2O Audio Sonar are a mixed bag for sound quality, not because they’re bad, but because they’re very dependent on positioning and situation. Getting the drivers on the cheekbones close to the ear, just touching the edge of the tragus, produces the best sound in my experience. Further away, treble starts to drop off considerably, and it was already limited to start.

Outside of water, the H2O Audio Sonar offer mellow but satisfying sound with rich mids and crispness at the upper end of mids. Bass and treble are fairly lacking here, but that’s the start of the story. Once you dip your head below water, where these headphones are meant to live, the sound suddenly shifts from mild to monstrous.

Submerged, it’s not just your bones that the sound is transmitting through but also the water near your ears. This gives the sound a much bigger presence, boosting the bass substantially. For an energetic pump-up track to get in the workout mood, it’s excellent. It’s not the most precise listening, with the bass suddenly outweighing the rest of the sound, but it’s exciting nonetheless. Since the headphones don’t cover your ears, you can still readily hear the beep of a set timer or a coach’s instructions when your head is out of the water, too.

Battery and charging

H2O Audio Sonar bone conduction headphones and their charger

The H2O Audio Sonar battery is rated to run for 7 hours, and that figure checks out. After an hour of playing music at 50% volume, which is plenty, the system was still reporting battery levels at 100%. It’s fairly common for devices to only report battery levels in large increments, and these headphones should still be in the 80-100% range after an hour of playback.

After two hours, the headphones reported 75% battery remaining, which lines up nicely with the 7-hour rated runtime. That’s about enough time for the strongest swimmers in the world to swim across the English Channel, so it should do nicely for most casual swimmers looking for a bit of music in the pool.

Competition

Source:James Holland

The H2O Audio Sonar has some competition from other bone conduction headphones, but there are few quite like it. The Finis Duo is close, offering a design that’s functionally the same except it puts all the controls on one side of the system. At $109, it’s a little more expensive, has half the storage for onboard audio, and lacks Bluetooth entirely, so the Sonar has a clear win here.

The rest of the competition is from neckband-style systems like the H2O Audio Tri or Shokz OpenSwim. The H2O Audio Tri offers the same features at the same price, but has a different design better suited to mixed use, where the Sonar reigns in the water. Meanwhile, the Skokz OpenSwim are more expensive at $150 while coming with less storage and the same neckband approach to the Tri headphones.

I’ll note there are also the H2O Audio Sonar Pro and Tri Pro, but they come with a substantial increase in price in order to get a dubious and tedious feature called Playlist+, which is simply a system for having the headphones make a recording of anything playing over Bluetooth and then save it to internal storage for later playback.

Should you buy them?

H2O Audio Sonar bone conduction headphones attached to swim goggles and sitting out

The H2O Audio Sonar serve one role: to give you some audio enjoyment while you slog away at your underwater workouts. They do that job well. They may not be pretty, but their ability to attach to your preferred goggles is a great way to easily integrate them with your swimming gear, and they’re very flexible as far as fit goes — something that wasn’t so for H2O Audio’s Tri Pro headphones.

While they may not be so versatile on land, still requiring a band to wear and failing to come anywhere close to the feature set of modest earbuds like the EarFun Air Pro 3, they deliver when its comes time to get wet, going deeper for longer than any of the typical earbuds you’ll find.

Source: H2O Audio

H2O Audio Sonar

The H2O Audio Sonar are a killer gadget for swimming. They can store audio files locally or play over Bluetooth from a smartwatch as long as both are connected to your goggles while you swim. In the water they offer pumpy sound to get you in the workout mood while keeping your ears open to hear lap timers and your surroundings. They may not be good for much on land, but swimmers won’t find much better options than these.