There are several different organizations around the world that offer self-contained underwater breathing apparatus, or SCUBA, diving certification. Many of these groups offer a variety of certifications, including basic permissions that allows a person to go on simple ocean dives without an instructor present, to more advanced and specialty certifications in areas such as deep ocean, night and cavern diving. While the groups generally operate independently, most have similar requirements for basic scuba certification and recognize each others certificates when it comes to organization-sponsored activities and clubs for certified divers.
One of the most well-known international scuba diving certification organizations is PADI, the Professional Association of Diving Instructors. The most common basic diving certification through PADI is the open water diver course, which anyone who is older than 10, is in good health and can pass a swimming test can generally take. This course typically requires time spent learning about the technical aspects of diving either in a classroom setting or online, as well as hands-on training in both a closed water setting, such as a pool, and in an open water setting, such as a lake or ocean. Once all of the training is successfully completed, student divers are usually awarded a diving certification card, also called a “C-card,” which allows them to go diving to depths of up to 60 feet (about 18.3 meters) without a certified diving instructor present.
PADI also offers many other certifications that typically allow divers to go deeper or to dive in more challenging conditions. For example, it offers a deep diver certification, which allows divers to go to depths of up to 100 feet (about 30.5 meters), as well as certifications that allow for dives on shipwrecks, in caverns and under ice. In general, each new diving certification through PADI and most other diving organizations requires additional coursework and hands-on training.
Another popular international diving certification agency is NAUI, the National Association of Underwater Instructors. NAUI offers a similar basic certification as PADI and has similar age, health and training requirements. It also offers a variety of specialty diving certifications, such as its advanced diver certification, which allows for dives up to 130 feet (about 39.2 meters). Other certification agencies include Scuba Schools International (SSI) and the British Sub Aqua Club (BSAC), the latter of which primarily services divers in the United Kingdom.
In general, most diving certification agencies recognize other agencies’ certifications as equally valid. This could be helpful, for example, if a diver has a basic NAUI certification and wants to take a PADI wreck diver course, which would normally have the basic PADI Open Water certification as a prerequisite. In such a situation, the PADI course would typically accept the NAUI certification as an equivalent, so the diver would not have to retake the same basic course again to move forward in his or her training. Similarly, the BSAC, which runs a diving club, generally accepts divers with any valid certification, not just those who are BSAC certified.