Sometimes you’ll see the word “waterproof” in the description of a spy camera. This means that you can safely use this camera under water. Some digital camcorders or mini surveillance cameras are designed to be water resistant. For monitoring activity in the pools or simply filming corals for entertainment. Waterproof spy cameras are engineered in such a way that they do not pass even a single water drop through the hermetically concealed casing.
The next question you should ask the seller is how deep you can dive with the mini camera. Some are designed for no more than 10 meters depth, while others can hold 30 meters without problems. For most people, for underwater recording, basic waterproof cameras will be just fine. You probably aren’t planning on deep sea diving, just filming underwater world near the beach that’s usually only a few meters deep.