The Professional Association of Diving Instructors (PADI) is the world's largest recreational diving membership organization and diver training organization.
PADI members, including dive centers, resorts, educational facilities, instructors, and divemasters, teach the majority of the world's recreational divers, issuing nearly 946,000 certifications each year. PADI operates offices in Australia, Canada, Switzerland, Japan, Sweden, the United Kingdom, New Zealand and the United States. The corporate headquarters, PADI Worldwide, is located in California, United States. PADI Offices serve more than 100,000 individual professional members and more than 4300 dive centers and resorts in more than 175 countries. Translations of PADI materials are available in more than 20 languages. PADI's market share worldwide is approximately fifty percent.
PADI courses range from entry levels (such as Scuba Diver and Open Water Diver) to master scuba diver and a full range of instructor certificates. The system is composed of standardized "modules" divided into theory and practice. Theory is mainly conveyed by way of self-study and confirmation of the student's level of knowledge in discussions with a diving instructor, while practice is obtained through training in pools and in open water. Upon completion of each course, a certificate is issued which is widely accepted as proof of proficiency throughout the world.
PADI courses are known for being shorter than other dive programs, and at the introductory level emphasize practical safety issues instead of theoretical concepts such as the physics and chemistry of diving. Other dive instruction programs have adopted similar techniques. Criticism of PADI programs has focused on their alleged high prices and less-rigorous standards for training.