SCUBA is short for "Self-Contained Underwater Breathing Apparatus." Scuba divers, while underwater, breathe through a mouthpiece that is attached to a tank of compressed air. Scuba diving is defined as pleasure diving to a depth of 130 feet.

Several scuba-certifying agencies offer training for divers, from beginners to experts. Three agencies that offer certification courses are the Professional Association of Diving Instructors (PADI), the National Association of Underwater Instructors (NAUI) and Scuba Schools International (SSI). Basic courses involve classroom instruction, training pools and open-water settings. Diving certification, which allows you to rent equipment, request tanks to be re-filled and dive without supervision, can be attained in as little as five open-water dives. Most scuba-certifying agencies highly recommend you dive in a "buddy system" (a group of 2 or 3 divers).