SDI TDI ERDI Japan is the Japanese national office for International Training's diving education agencies: SDI (Scuba Diving International) for recreational scuba courses, TDI (Technical Diving International) for deep, cave, wreck, sidemount and rebreather technical diving, ERDI (Emergency Response Diving International) for public-safety/search-and-rescue diver training used by police and fire services, and PFI (Performance Free Diving International) for freediving, alongside First Response Training International for CPR and first-aid courses. It supports Japanese instructors and affiliated dive centers with instructor crossovers, facility registration, C-card processing, e-learning, manuals and instructor guides, and runs its own online shop for training materials and branded gear. It also publishes a diving-accident report series and organizes instructor-level events such as Instructor Trainer Workshops in Japan.