There are some compact cameras like the Olympus TG series that are waterproof down to 15 meters. These cameras are descent enough for free diving and hobby shooting near the surface.
But if you want to get serious and into underwater photography you will need a housing. A housing protects your camera way better than any water-resistant camera design ever could both from external (scratches to lens and body and damage to buttons) and internal damage (damage to the hardware). With the new advances in housing technology (vacuum system and moisture alarm) you will be warned if there is the tiniest breach in your housing and you will most likely be able to get it topside and save it before anything bad happens. A housing not only protects your camera but is also a platform for designing your own rig and getting the best photos out of your dive. A housing lets you build onto it with trays to get a more stable shoot, add some arms for lights and get better quality photos, add a wet lens to capture all the details of even the smallest sea creatures.
With Fantasea Compact Housings for Canon and Sony cameras you get a nice midrange priced housing with lots of functionality and ergonomics built into the technology, that will serve your camera well in the time to come. Fantasea housing is a nice platform to build on and they are compatible with a lot of other lenses, viewfinders, trays and everything you will need to build your ideal system.
We here at Fotografit are always happy to help you tailor the best equipment for your personal needs. Feel free to contact us with your questions at our webpage fotografit.eu (chat with us) or on our mail firstname.lastname@example.org.