Imagine gliding effortlessly through a crystal-clear tropical ocean, marveling at rainbow-hued fish flitting about a vibrant coral reef. Chances are you’ve seen this on TV, in movies or perhaps a friend’s underwater video — but to experience it, you must become a scuba diver.

While scuba does involve a certain degree of physical exertion, it’s one of the easiest recreational activities to learn. All you need is a reasonable level of fitness, the ability to swim and the willingness to undergo a training program. Depending on the training agency, this may last from a few days to weeks and consist of confined water sessions and open water dives.

The scuba training process involves a number of skills that are practiced in a swimming pool, such as entering and exiting the water, breathing, clearing a mask and making safe and controlled descents and ascents. You’ll also learn to recognize marine life and master dive safety procedures. Most scuba divers learn to enjoy marine life, and this often inspires them to become advocates for ocean conservation. Many participate in reef clean-ups and other citizen science projects that help protect fragile ecosystems.

A scuba dive requires specialized equipment, including a demand valve regulator, air cylinder and buoyancy compensator. The air cylinder contains filtered, compressed nitrogen, which is not metabolized by the human body, so it doesn’t build up in the tissues and cause decompression sickness (the bends). You’ll also need to wear a wetsuit, made of neoprene rubber that consists of thousands of tiny air pockets that add considerable buoyancy.