TDI Extended Range Diver
Go deeper, manage complex decompression, and operate at the limits of air-based technical diving
Overview
The TDI Extended Range Diver course is designed to train divers to conduct dives beyond the limits of standard decompression procedures, using air as a primary gas and accelerated decompression techniques.
This programme builds on Advanced Nitrox and Decompression Procedures, introducing deeper exposures, increased narcosis management, and more complex dive execution. Divers will learn to plan and conduct dives requiring staged decompression to depths of up to 55 metres, using nitrox and oxygen for accelerated decompression.
At N9BO℠, this is where technical diving becomes fully operational — requiring discipline, precision, and strict adherence to procedures under increased depth, gas density, and task loading.
Course Facts
- Course name: TDI Extended Range Diver
- Level: Advanced technical decompression course
- Minimum prerequisites: Minimum age 18, TDI Advanced Nitrox Diver and TDI Decompression Procedures Diver (or equivalents), minimum 100 logged dives with at least 25 dives deeper than 30m
- Ratio: A maximum of 4 students per instructor (small groups recommended for quality training)
- Configuration: Technical configuration (backmount doubles or sidemount) with multiple stage/decompression cylinders
- Depth / environment: Maximum 55m / 180ft with mandatory staged decompression
- Format: Academic development + confined/open water skills + staged decompression dives
- Duration: Typically completed in 4 days (Minimum 4 dives with at least 100 minutes cumulative bottom time; all dives deeper than 30m, with at least 2 dives deeper than 40m)
What You’ll Learn
- Plan and execute deep decompression dives using air as a bottom gas.
- Manage narcosis and increased gas density at depth.
- Use multiple decompression gases including high-oxygen mixes.
- Execute complex ascent profiles with staged decompression.
- Maintain control, awareness, and team coordination under increased task loading.
Prerequisites
- Be at least 18 years old.
- Hold certifications in Advanced Nitrox and Decompression Procedures (or equivalent).
- Provide proof of at least 100 logged dives, including 25 dives deeper than 30m.
- Be medically fit for diving.
FAQ
This course is for technical divers who want to extend their depth and range using air, and who are ready to manage deeper decompression dives with increased complexity.
Extended Range increases both depth and complexity. It introduces deeper exposures, greater narcosis considerations, and more demanding gas management compared to standard decompression training.
You will conduct four decompression dives, all deeper than 30 metres, with progressively increasing depth and complexity. At least two dives will exceed 40 metres, requiring precise execution of gas switches and decompression schedules.
This course is conducted using air as the primary bottom gas, with nitrox or oxygen used for decompression. It prepares divers for trimix training but does not include helium.
You will be qualified to plan and conduct decompression dives using air to a maximum depth of 55 metres, within conditions similar to training and with appropriate equipment and team support.
Ready to Push Your Limits?
Send us your certifications, experience, and training goals. We’ll help you move into deeper, more demanding technical diving with the right structure and progression.
Go Pro with TDI Extended Range Instructor
Take your technical diving to the professional level and start teaching deep decompression diving. Delivered by a TDI Instructor Trainer, this pathway builds the control, discipline, and instructional ability required to train divers safely at extended range depths.
