I spent 2 weeks testing the H2O Audio Sonar 2 Pro, and found them to be the perfect headphones for swimming | Tech Radar

Overview

I spent 2 weeks testing the H2O Audio Sonar 2 Pro, and found them to be the perfect headphones for swimming

Between the form factor and features, this is one of the best for the pool

Details

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

The H2O Audio Sonar 2 Pro does a lot right for the pool. Its form factor is very limiting, but ideal for use with goggles or a headband while swimming. The onboard MP3 player along with the Playlist+ feature get around the pesky Bluetooth in water problem. Unfortunately, the overwhelming low-end can’t be adjusted.

The best swimming headphones 2026: Top waterproof bone conduction headphones

The best bone conduction headphones 2025: Stay aware on the road, in the pool and the office

We spend hours testing every product or service we review, so you can be sure you're buying the best. Find out more about how we test.

The H2O Audio Sonar 2 Pro are possibly the best possible headphones for serious swimmers. They secure onto a headband instead of having their own (and are very stable when in place), making them unique among H2O Audio’s offerings as well as setting them apart from the rest of our best swimming headphones. Since Bluetooth connectivity has trouble in water, H2O has added some features to get around that.

As good as the H2O Audio Sonar 2 Pro are for swimmers, they’re 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 quite an audiophile experience. And that form factor is very limiting. While some of our best running headphones list use bone conduction technology and can be used in water and on land, there are other options, even from H2O Audio, that I prefer for that purpose, such as the H20 Audio Tri 2 Pro, rated our best bone conduction headphones overall.

But for their intended purpose, you’ll be hard-pressed to do better than the H2O Audio Sonar 2 Pro. With that in mind, let’s dive a little deeper on 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 Air Pods come in – nor how small the soft-shell case inside was, which was basically the same size as the box.

The actual headphones came inside the case along with the folded up charging cable and a pair of waterproof earplugs. The headphones themselves, besides being fairly small, are unique looking because they have no headband of their own, just a thick, blue cable that goes behind one’s head connecting the drivers to each other.

The bone conduction drivers are each in black housing with a clip on the outside and three control buttons – the left has the 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.

Since these are made for swimming, they have an IPX8 rating – about as good as it gets in any consumer product not meant for the Mariana Trench – so it can be underwater “up to 12ft/3.6m” without any restriction. If you’re considering these for serious diving, be warned the pressure in deeper waters could affect these headphones.

Also, since the H2O Audio Sonar 2 Pro are made for swimming, they come with a couple features meant to circumvent one of the biggest hurdles for using headphones while swimming. Bluetooth connectivity tends to become more intermittent the more water is between the source like a smart phone and headphones, so these headphones come with a built-in MP3 player with 8GB of storage.

Loading music onto these headphones then is reminiscent of loading music onto a phone as one might have 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 that you have to have the music you want stored in playable form like MP3 on your computer.

The H2O Audio Sonar 2 Pro do have an additional feature to make this more manageable that the non-Pro version doesn’t have, and that’s the Playlist+ feature. This feature lets the user load music onto 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+ feature like a tape recorder. Whether you do it through the headphones (you 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 is done. It won’t stop on its own, so you could potentially have multiple songs on one track. One thing that I do appreciate is that it will read the name and song title from the source and automatically name the file after it. It’s a nice work-around, if a little inelegant. It’s literally a digital version of pressing ‘record’ on a boombox to make a mixtape.

Regardless of whether you’re streaming through 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 bit strange. The way bone conduction headphones work affects the sound quality a little, since what you’re listening to is vibrating through your cheekbones into the inner ear instead of actually passing through your ear. So, everything sounds more intelligible when also wearing the included earplugs.

It also sounds clearer when underwater. The listening experience is not quite Hi Fi, however. I’ve listened to H2O Audio products underwater before and I don’t remember them being as bass-heavy. Maybe it’s intentional to make the music sound more motivating but the low-end 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 are somewhat overpowered by the kick drum.

What’s strange is that there’s no real way to EQ the headphones in a way to offset it, especially if you’re using Memory Mode (you can always use an EQ on the phone for Bluetooth audio). That said, the mids and highs are fairly clear when underwater, so if H2O Audio adjusted their app to have some kind of EQ adjustments, I think these headphones would be even easier to recommend.

They’re still easy to recommend, despite that issue with the low-end. I haven’t really discussed fit yet, and while you’re somewhat at the mercy of whatever headband you use, when these slip on they’re incredibly stable. They don’t move. They don’t jiggle. I learned by struggling or thrashing my way through a couple laps in an Olympic pool to see what would happen. This is a big reason why they’re among the best swimming headphones.

There’s not else to write home about regarding the H20 companion app, other than to mention that it will give you a readout of battery life and let you navigate the songs stored on the device when in memory mode. You can also start the Playlist+ feature here.

Lastly, the 10-hour battery life doesn’t seem impressive compared to what we see on the best wireless earbuds, especially when you include the extra charges in their carrying case – something you don’t get with the soft shell case as it’s not a power source. But I think it’s actually a decent amount of juice for a swimmer.

How much does it cost?

Where can you get it? Available in the US, UK, and Australia

The H2O Audio Sonar 2 Pro aren’t cheap, but the price is very respectable at

Many of the swimming headphones and bone conduction headphones end up going for at least the same price if not more. The Shokz Open Swim Pro, for example, go for a slightly higher

Even the company’s own H2O Audio Tri 2 Pro Multi-Sport has a higher MSRP

The price tag for these headphones are pretty reasonable as one could definitely pay more for swimming headphones.

The price tag for these headphones are pretty reasonable as one could definitely pay more for swimming headphones.

Though a niche design, the H2O Audio Sonar 2 Pro are ideal for swimmers thanks to how secure they are.

Though a niche design, the H2O Audio Sonar 2 Pro are ideal for swimmers thanks to how secure they are.

The sound quality, though a bit bass-heavy, is clear underwater. Plus, the battery life is more than enough.

The sound quality, though a bit bass-heavy, is clear underwater. Plus, the battery life is more than enough.

It may be niche, but swimmers needing headphones that clip in will be thrilled with these.

It may be niche, but swimmers needing headphones that clip in will be thrilled with these.

The clip-on design make these about as stable as one gets for swimming. Add in the MP3 player and Playlist+ feature and you have ideal headphones for doing laps.

The Playlist+ feature is very helpful for getting your playlist or any music / podcast you don’t own onto the headphones, and it’s a feature that one only gets with H2O Audio.

You want bone conduction headphones for any other reason

If you don’t need headphones that clip into the headband of swimming goggles, then look elsewhere including H2O Audio’s other offerings.

If you don’t want to deal with plugging the headphones into your computer and transferring music or queuing up a playlist and running the Playlist+ feature, you’re missing out on a good portion of what sets these headphones apart.

The Shokz Openswim Pro are waterproof with a comfortable and tight fit, even if they don’t clip into a headband, and come with a good nine hours of battery life. It’s not the most up-to-date of Shokz headphones but is still an ideal option for swimmers.

The H2O Audio Tri 2 Pro Multi-Sport aren’t cheap, but are worth it, especially for anyone also looking for headphones to use during swimming. After all, these are tailored to triathletes.

Read our full H2O Audio Tri 2 Pro Multi-Sport review

I spent a couple of weeks testing the H2O Audio Sonar 2 Pro including a couple laps in an Olympic size pool as well as just hanging out underwater to listen to them. While using them, I listened to all sorts of genres from electronic and hip-hop to rock and acoustic music to get an idea of how they sound. I also tested the various features, most notably the Playlist+ feature.

After testing, it’s clear that these are ideal for serious swimmers, not only from the bone conduction but the form factor, which means that they’re as secure as a pair of headphones can be during a swim. 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 have spent even longer using my critical ear as a listener and musician to understand what does and doesn’t sound good.

James Holland loves checking out gadgets of all sorts, whether it's audio equipment, laptops, or vacuums (especially of the robot variety), and does so for a number of Future Publications including Tech Radar, Top Ten Reviews, Homes & Gardens, and T3. He's built up an expertise for in-depth reviewing over the last four years. When he's not putting in the work on the latest tech, he loves to travel, play music, and eat questionable food.

You must confirm your public display name before commenting

1 It's about time: Your Samsung Galaxy S26 can now Air Drop files to an i Phone

2 Did Kioxia just unveil the fastest SSD ever? GP series uses Storage Class Memory to feed the HBM GPU with millions of IOPS

3 System 76 charges $5299 for an Nvidia Ge Force RTX 5090 GPU upgrade on its latest PC

4 Apple’s long obsession with colorful computers started in 1979

544 bathroom trips later: My unfiltered thoughts on the P Water app

Tech Radar is part of Future US Inc, an international media group and leading digital publisher. Visit our corporate site.

© Future US, Inc. Full 7th Floor, 130 West 42nd Street, New York, NY 10036.

Key Takeaways

• I spent 2 weeks testing the H2O Audio Sonar 2 Pro, and found them to be the perfect headphones for swimming

• Between the form factor and features, this is one of the best for the pool

• When you purchase through links on our site, we may earn an affiliate commission

• The H2O Audio Sonar 2 Pro does a lot right for the pool

• The best swimming headphones 2026: Top waterproof bone conduction headphones