Meet the Seawolf: a remotely operated underwater vehicle for carrying HD sports cameras such as the GoPro HERO4. It lets you take still photos and videos, live stream video, and more. It has a high-impact ABS hull and 2.4 Ghz wireless control. The below video shows the Seawolf in action:
You get a tough Pelican case, a tether reel, and a Boscam D4 device with a 8″ LCD screen and a 5.8 GHz receiver with your purchase. Just bring your action camera, and you are set.