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H2O Audio Sonar 2 Pro: Two-Minute Review
The H2O Audio Sonar 2 Pro are arguably the best headphones possible for serious swimmers. They attach to a headband rather than having their own (and are very stable when in place), making them unique among H2O Audio's offerings and setting them apart from the rest of our best swimming headphones. Since Bluetooth connectivity has issues in the water, H2O has added some features to fix it.
As good as the H2O Audio Sonar 2 Pro are for swimmers, they are probably among the least interesting headphones for any other purpose. They only sound good underwater (this is by design, of course) and it's still not a completely audiophile experience. And that form factor is very limiting. While some on our list of the best headphones for running use bone conduction technology and can be used in water and on land, there are other options, including from H2O Audio, that I prefer for that purpose, such as the H20 Audio Tri 2 Pro, rated as our best bone conduction headphones overall.
But for its intended purpose, you'll be hard-pressed to do better than the H2O Audio Sonar 2 Pro. With that in mind, let's delve a little deeper into why that is.
While I already had an idea of what to expect when I received these headphones, I was surprised by how small the box was (it's not much bigger than the box the AirPods come in) or how small the soft case inside was, which was basically the same size as the box.
The actual headphones came inside the case along with the folded charging cable and a pair of waterproof earplugs. The headphones themselves, in addition to being quite small, have a unique look in that they have no headband of their own, just a thick blue cable that goes behind the head and connects the drivers to each other.
Each of the bone conduction controllers has a black casing with a clip on the outside and three control buttons: the left has Mode (switches between Bluetooth mode and using internal storage in Memory Mode), forward and back, while the right has Play/Pause/Power and Volume Up/Down.
Because they're made for swimming, they have an IPX8 rating—almost as good as any consumer product not designed for the Mariana Trench—so they can be underwater “up to 12 feet/3.6 m” without any restrictions. If you are considering them for serious diving, keep in mind that the pressure in deeper water could affect these headphones.
Additionally, since the H2O Audio Sonar 2 Pro is designed for swimming, it comes with a couple of features aimed at getting around one of the biggest obstacles to using headphones while swimming. Bluetooth connectivity tends to become more intermittent the more water there is between the source, like a smartphone, and the headphones, which is why these headphones come with a built-in MP3 player with 8GB of storage.
Loading music on these headphones is then reminiscent of loading music on a phone as could have been done ten years ago, which is not the most convenient, using the included charging cable and connecting the headphones to a computer. That also means you must have the music you want stored in a playable format like MP3 on your computer.
The H2O Audio Sonar 2 Pro has an additional feature to make it more manageable than the non-Pro version, and that is the Playlist+ feature. This feature allows the user to load music to the headphones wirelessly. Now, H2O Audio advertises this feature as a way to transfer a playlist, but that overcomplicates what this feature actually does.
Think of the Playlist+ function as a recorder. Whether you do it through the headphones (press the Volume Up button twice to start and stop recording) or the app, you basically start the recording process, press play on whatever music or podcast you want, and then stop it when the song ends. It won't stop on its own, so you may have multiple songs on one track. One thing I appreciate is that it will read the name and song title from the source and automatically name the file after you. It's a good solution, although a bit inelegant. It's literally a digital version of pressing “record” on a boombox to make a mixtape.
Regardless of whether you are streaming via Bluetooth or listening to an MP3 in memory mode (aka the built-in MP3 player), the sound quality is the same. And it's a little strange. The way bone conduction headphones work affects the sound quality a bit, as what you're hearing vibrates through your cheekbones and into your inner ear instead of actually passing through your ear. Thus, everything sounds more intelligible if you also have the included earplugs.
It also sounds clearer underwater. However, the listening experience is not entirely HiFi. I've heard H2O Audio products underwater before and I don't remember them having that much bass. Maybe it's intentional to make the music sound more uplifting, but the bass seems to be front and center to the point where a song like “In-A-Gadda-Da-Vida” sounds like a bass solo and songs with 808 drums like hip-hop and EDM become somewhat dominated by the kick drum.
The strange thing is that there's no real way to EQ the headphones to compensate for them, especially if you're using memory mode (you can always use an equalizer on the phone for Bluetooth audio). That said, the mids and highs are pretty clear when underwater, so if H2O Audio adjusted their app to have some sort of EQ settings, I think these headphones would be even easier to recommend.
They are still easy to recommend, despite the problem with the low end. I haven't really talked about the fit yet, and while you're at the mercy of whatever headband you use, when they slide on they're incredibly stable. They don't move. They don't move. I learned by struggling or crawling through a couple of laps in an Olympic pool to see what would happen. This is one of the main reasons why they are among the best headphones for swimming.
There's nothing else to note about the H20 companion app, other than to mention that it will give you a readout of your battery life and allow you to browse songs stored on the device when it's in memory mode. You can also start the Playlist+ function here.
Lastly, the 10-hour battery life doesn't seem impressive compared to what we see in the best wireless earbuds, especially when you include the extra charges in their carrying case, something you don't get with the soft case since it's not a power source. But I think it's actually a decent amount of juice for a swimmer.
H20 Audio Sonar 2 Pro: Specifications
|
Component |
H20 Audio Probe 2 Pro |
|
Drivers |
bone conduction |
|
Active noise cancellation |
No |
|
Battery life |
Up to 9 hours |
|
Weight |
1.0 oz (29 grams) |
|
Connectivity |
bluetooth 5.3 |
|
Frequency range |
30Hz – 18kHz |
|
Waterproofing |
IPX8 |
|
Other features |
8GB storage and MP3 player, Playlist+, app support |
H2O Audio Sonar 2 Pro: Price and availability
- How much does it cost? $149.99 / £117.00 / AU$234.00
- When will it be available? Available now
- Where can you get it? Available in US, UK and Australia
The H2O Audio Sonar 2 Pro isn't cheap, but the price is very respectable: $149.99 / £117.00 / AU$234.00. Considering the feature set and specific use, I could see a higher price (although I hope H2O Audio provides more control over the EQ before that happens).
Many of the swimming and bone conduction headphones end up costing at least the same price, if not more. The Shokz OpenSwim Pro, for example, costs a slightly more expensive $179.95 / £169 / AU$299. They also have a built-in MP3 player, but they don't have anything like the Playlist+ feature (which is a proprietary H2O feature). They also have the more typical form factor of a pair of bone conduction headphones with a sturdy yet flexible headband.
Even the company's H2O Audio Tri 2 Pro Multi-Sport has a higher MSRP of $199.99/£155.68 (around AU$310). Of course, they are intended for a different purpose. They are durable and stable enough for swimming, but do not snag as they are intended for running as well. They also come with Playlist+ feature.
|
Attributes |
Grades |
Classification |
|---|---|---|
|
Worth |
The price of these headphones is quite reasonable, as you could definitely pay more for headphones for swimming. |
4/5 |
|
Design |
Although it has a specialized design, the H2O Audio Sonar 2 Pro is ideal for swimmers thanks to its safety. |
4.5/5 |
|
Performance |
The sound quality, although a little bassy, is clear underwater. Plus, the battery life is more than enough. |
4/5 |
|
Average rating |
It may be niche, but swimmers who need clip-on headphones will be pleased with these. |
4/5 |
Should I buy the H2O Audio Sonar 2 Pro?
Buy it if…
Don't buy it if…
Also consider
how i tried it
- Tested for a couple of weeks
- I listened to different genres of music.
- I tried all the different features.
I spent a couple of weeks testing the H2O Audio Sonar 2 Pro, including a couple of laps in an Olympic-size pool and just hanging out underwater to listen to them. While using them, I listened to all kinds of genres, from electronic and hip-hop to rock and acoustic music, to get an idea of what they sound like. I also tried the different features, especially the Playlist+ feature.
After testing, it's clear that they are ideal for serious swimmers, not only because of the bone conduction but also the form factor, meaning they are as safe as a pair of headphones can be while swimming. Check out our guide to how bone conduction headphones work for more details on how headphones like these work.
I've spent the last few years reviewing audio equipment and I've spent even more time using my critical ear as a listener and musician to understand what sounds good and what doesn't.
- First review in November 2025
