The GoPro Hero 5 is a fantastic underwater camera. However, there is a catch. The device cannot submerge on its own. Rather, it requires a Super Suit Dive Housing (also from GoPro) to get wet. Even so, that accessory turns it into one of the best diving cameras around. The device is able to go down to 196 feet and comes with a bright 2-inch touchscreen display that is easy to use while swimming. The ultra-wide angle lens, 4k recording capabilities, and 12MP image resolution bring it all together.
Also note that their newest line of cameras, the HERO3+ (plus) are only smaller in size and lighter in weight. As of now, the Black Edition for both Hero3 and Hero3+ are only a few dollars different in terms of price, so go for the plus! And now that the HERO4's are out, check the prices of previous versions as they'll be dropping slowly. Unless of course you want the newest of the new, check out their HERO4!
aqua view underwater camera
The reason I ask what you will be using it for is to determine which set of features you need. If you're going to be using it for simpler activities, don't go all out for a Black edition with a 60fps, 1080p cam (all HERO3's are 1080p, anyways). The reason the Black Edition is so expensive is because of the crazy quality it has, and if you're using it for a more simple basis I wouldn't worry about the difference. The Silver or even White is perfectly fine for you. The main difference between these two is the white's camera has a 5 megapixels with 3fps burst while the silver is 11 megapixels with a 10 fps burst -- is that worth $100 to you?
Is GoPro still the best action camera?
Ensure you can easily use your camera before purchase. This is an aspect many people overlook when getting a new GoPro, and it can cost them down the line. There are many bells and whistles tied to cameras. Though they might look great, you don’t want a model you aren’t able to operate. That does not mean you have to get the simplest model out there, but you should get one that is in your comfort zone.
And sure, those options could include your waterproof and crack-resistant smartphone, but keep in mind that the best action camera is designed for this kind of shooting. Plus, just because your phone is tougher, it doesn't mean you should risk losing or damaging the thing that keeps you connected to work, family and friends. It's also way easier to mount one of these to your body, car, bike or anything else than your phone.