Underwater imaging is considered an especially challenging area of photography, since it requires very specialized equipment and techniques to be successful. Despite these challenges, it offers the possibility of many exciting and rare photographic opportunities. Animals such as fish and marine mammals are the most common subjects, but photographers also pursue shipwrecks, submerged cave systems, underwater “landscapes”, and portraits of fellow divers.
Since underwater photography is often performed while scuba diving, it is important that the diver-photographer be sufficiently skilled so that it remains a reasonably safe activity. Good scuba technique also has an impact on the quality of images, since marine life is less likely to be scared away by a calm diver, and the environment is less likely to be damaged or disturbed. There is the possibility of encountering poor conditions, such as heavy currents, tidal flow, or poor visibility. Generally, underwater photographers try to avoid these situations whenever possible.
You can find more information at Wikipedia
Below we present 50 awesome examples of Under Water Photography. All photos are linked and lead to the sources from which they were taken. Please feel free to explore further works of these photographers on their collections or their personal sites.