The Naenka Runner Diver is a bone-conduction headphone that offers Bluetooth and music player streaming in one package, designed for underwater use.

This follow-up to Naenka's Runner Pro offers more storage for stacking audio and a larger battery for longer use in and out of the water. [This makes the Runner Diver an attractive option for those looking for waterproof bone-conduction headphones.

The Naenka Runner Diver is priced at $149/£119/$223 AUD, comparable to the Shokz OpenSwim ($149/£169/$239 AUD). like the Creative Outlier Free Pro, a more There are also cheaper waterproof bone-conduction alternatives.

The Naenka Runner Diver can be purchased directly from the Naenka website or from online retailers including Amazon.

Runner Diver draws design inspiration from an interesting source: seahorse-like neckband headphones.

Aside from the seahorse-inspired design, the headphones are made from a mix of titanium and silicone, making them lightweight and comfortable to wear even in critical areas where they hit the head. Weighing 1.20 ounces (about 35 grams), the bulkiest part is where the 16GB of music player storage is located.

The IPX8-rated design means it is suitable for submersion in water up to 1.5 meters, and Naenka says it should not be used underwater for more than 40 minutes at a time.

There are a series of physical buttons for adjusting audio volume and skipping audio, as well as dedicated buttons for switching between Bluetooth streaming music player modes and turning the headphones on and off. A single microphone is included to make calls and speak to a smart assistant, and a microphone protection plug is included to hide the microphone if it gets into water.

In terms of fit and prolonged wear, there were no problems in my tests. It stays securely in place underwater, but it is worth securing it under a swim cap for added safety. Controls are well placed, both in a fixed position and on the move. They are certainly not the slimmest or lightest bone-conduction headphones, but they are not uncomfortable to wear either.

Whether you use the Runner Diver in Bluetooth streaming or in music player mode, sound arrives in exactly the same way using bone conduction technology. Therefore, the sound is transmitted through the transducer over the cheekbone and into the ear without blocking the ear, so you can hear the song being played as well as the surrounding noise at the same time.

The music player mode is designed primarily for underwater use and requires first connecting the headphones to a computer via a USB port and transferring audio files to the headphones by dragging and dropping files. The version of Diver I tested supports MP3 and FLAC files, but there are updated versions that support M4A, WAV, and APE files. It is not possible to load music from streaming services, but this would definitely be a desirable feature.

Once the 16 GB of storage and up to 2,400 songs are utilized, there is an option to play audio in order with random playback, which is supported by the updated Runner Diver. To make good use of the music player, I had to dig through the archive of songs purchased on iTunes and download several podcasts, both music and conversation-based.

Overall, the streaming mode was very good, both in and out of the water. The Naenka also comes with earplugs to help block out sound when used for swimming, but I found that the sound was enjoyable enough to use the headphones without earplugs.

Much of the music I kept was more bass-heavy dance and drum 'n' bass tracks, but the Runner Diver successfully handled the more bass-focused sounds without destroying the highs and mids. Detail and clarity were reproduced well when needed, and switching to a conversation-oriented podcast worked well. There was none of the emptiness or muddiness that one might expect during a swim.

Coming out of the water and using either Bluetooth streaming or a music player provided versatility, clarity, and a slight bass that resonated pleasantly; listen to Spotify's Songs To Test Headphones playlist (or Tom's Guide Headphone Demo playlist), bass is reproduced well on songs like Burial's "Archangel." On Otis Redding's "(Sittin' On) the Dock of the Bay," the vocals sound pleasantly warm and there is enough detail in the treble to make it suitable for podcasts and audiobooks.

If you want to make or receive phone calls, the Runner Diver can be said to do an acceptable job, but they are not the headphones to rely on to handle regular call times. We tested call quality while working in a quiet room and outdoors where there is a lot of environmental noise, such as wind and traffic. Since there is only one microphone here, increased noise can degrade the sound quality heard during a call, making it seem quieter and emptier. It definitely performs better in quiet indoor environments.

Naenka suggests that up to 10 hours of battery life can be expected from the Runner Diver, which is the same battery life promised by the similarly priced Shokz OpenRun Pro. and the playback time drops noticeably when listening at higher volumes.

Ten hours is possible, but if you are using a music player streaming, it will be about half of that, as the on-board streaming apparently demands more power from these bone-conduction headphones.

When the battery power reaches zero, it takes 1.5 hours to fully charge again using the proprietary charging cable. Unfortunately, there is no fast charging mode that can be used immediately if you forget to charge the battery.

The Naenka Runner Diver allows you to enjoy bone-conduction sound whether you swim with or without it on, and has good battery life whether you listen via Bluetooth or make good use of the onboard music player.