| Abbreviation | Definition |
|---|---|
| NDU | Naval Diving Unit |
| NEDU | Navy Experimental Diving Unit |
| NSDS | Naval Service Diving Section |
| NSL | National Skydiving League |
| OBDC | Only Babes Dive Club |
| OCDA | Ozark Cave Diving Alliance |
| OPL | Optimum Performance Level |
| OSDT | Oxford Swimming and Diving Team |
| PADI | Professional Association of Diving Instructors |
| PCDS | Pacific Commercial Diving Supply |
| PDIC | Professional Diving Instructors Corporation |
| PDRA | Piedmont Diving and Rescue Association |
| PFI | Performance Freediving International |
| PSDA | Public Safety Diving Association |
| RAID | Rebreather Association of International Divers |
| RNT | Residual Nitrogen Time (Diving) |
| SDB | A Scuba Diving Bulls |
| SDI | Scuba Diving International |
| SDVP | Scuba Diving Vinkeveense Plassen |
| SDW | Swiss Diving Watch |