The Open Water EANx Instructor course is a scuba diving instructor certification program offered by many scuba diving organizations, including IANTD, PADI, and SSI. The course is designed to teach experienced scuba diving instructors how to teach students how to safely and effectively use enriched air nitrox (EANx) as a breathing gas while diving.

The course typically consists of classroom sessions, confined water dives, and open water dives, and covers a range of topics including the benefits and risks of EANx diving, gas management, equipment considerations, dive planning and execution, analyzing and labeling EANx cylinders, and using EANx tables or dive computers.

During the course, students learn how to teach the knowledge and skills necessary for students to safely and effectively use EANx, including how to analyze gas blends, calculate maximum operating depths, and plan and execute EANx dives.

To enroll in the Open Water EANx Instructor course, students must be certified as scuba diving instructors with a recognized scuba diving organization. They must also have a minimum number of logged dives, meet the age requirement (usually 18 years old), and have completed a Nitrox Instructor course or equivalent.

Throughout the course, safety is emphasized, and students are trained to manage risks associated with EANx diving. They learn to teach students to use the appropriate equipment, plan and execute safe and controlled dives, and manage their gas supply.

Upon successful completion of the course, students will be certified as Open Water EANx Instructors and will be qualified to teach students how to safely and effectively use EANx as a breathing gas while diving. They can also go on to become technical diving instructors, teaching more advanced diving courses.