The Open Water EANx Diver course offered by the International Association of Nitrox and Technical Divers (IANTD) is a specialized scuba diving certification program that focuses on using enriched air nitrox (EANx) as a breathing gas while diving. The course is designed for divers who want to extend their no-decompression limits, reduce the risk of decompression sickness, and increase their bottom time.

The course typically includes a combination of classroom sessions, pool or confined water dives, and open water dives. During the course, students will learn about the benefits and risks of using EANx as a breathing gas, the physics and physiology of EANx diving, gas management, equipment considerations, and dive planning and execution.

The course also includes hands-on training in analyzing and labeling EANx cylinders, calculating equivalent air depths and maximum operating depths, and using EANx tables or dive computers to plan and execute EANx dives.

To enroll in the Open Water EANx Diver course, students must be certified as Open Water Divers or have an equivalent certification from a recognized scuba diving agency. They must also meet the minimum age requirement (usually 15 or 18 years old), and have a minimum number of logged dives.

Upon completion of the course, students will be certified as Open Water EANx Divers, which allows them to dive with EANx blends up to 40% oxygen, within their limits and training, using the knowledge and skills they have learned during the course.