But which one?
Boson.com has you covered.
The web site just published a review of four of the most popular underwater MP3 players on the market.
According to the web site the pros and cons are:
NU TECHNOLOGY DOLPHIN
Price: $99-$115, depending on storage size
Pros: The 2.4-inch-long Dolphin was the lightest and smallest of the group. Its simple, tube-shaped design made it the easiest to wear. Its headphones were also the most comfortable of the group. Offers up to eight hours of playtime per charge.
Cons: Small buttons make it difficult to scan your music files without looking at the device, though we got used to it after a short amount of time.
The final word: This player offers comfort and high-quality sound at a reasonable price.
Pros: The Aquabeat features a prominent forward-back button that makes flipping through songs easy, even when the device is strapped to the back of your head. It offers up to nine hours of playtime per charge.
Cons: Music often sounded tinny, and it makes an annoying beep if you skip a song.
The final word: The Aquabeat might be a good option for those with dexterity problems, but the sound doesn't merit the price.
FINIS SWIMP3 V2
Pros: The SwiMP3's paddle design offers an alternative for people who don't like to wear headphones. The device's sound is very clear, especially underwater. Offers eight hours of playtime per charge.
Cons: The device can be awkward and uncomfortable to wear underneath goggles, which in our case had to be tightened to hold the slippery paddles in place.
The final word: The SwiMP3's rich sound makes it worth trying, though its innovative design costs more.
FREESTYLE AUDIO SOUNDWAVE
Pros: The Soundwave was the cheapest of the group, and the only device that offered a radio feature. It also offers 18 hours of playtime per charge, the most among the players we tried.
Cons: It's bulky and awkward to wear, especially when connected to a goggle strap. The device can also be worn with an armband, but the cord can get in the way for swimmers. It features a screen that tells you the radio frequency, name of the song file, and helps you change settings, but it's challenging to navigate.
You can read the entire review HERE.