TDI Advanced Nitrox Course

Standard nitrox certification qualifies you to dive enriched air up to 40% oxygen. That covers a lot of recreational diving and extends your no-decompression limits meaningfully. But the technical diving track runs on gases well above that threshold, and the TDI Advanced Nitrox course is where you gain the training to use them.

The course qualifies you to dive gas mixes from EAN 21 through 100% oxygen on no-decompression dives to a maximum depth of 130 feet (40 metres). It covers everything that changes when oxygen percentages go above 40%: the physics and physiology, the planning, the equipment requirements, and the gas analysis and blending procedures that high-O2 diving demands. It is often taught alongside TDI Decompression Procedures, and together those two courses form the foundation most technical divers build on.

Who This Course Is For

• Certified nitrox divers who want to use gas mixes above 40% oxygen and understand the additional physics and physiology involved
• Divers pursuing technical training who need Advanced Nitrox as a prerequisite for TDI Decompression Procedures
• Semi-closed or closed-circuit rebreather divers, for whom Advanced Nitrox certification is required

What the Course Covers

Physics and Physiology of High-Oxygen Mixes

As oxygen percentage increases, so do the risks associated with oxygen toxicity. The course covers the physics of how higher oxygen partial pressures behave at depth, the physiology of central nervous system (CNS) oxygen toxicity and pulmonary oxygen toxicity, how to calculate and track oxygen exposure limits across a dive, and how nitrogen narcosis interacts with high-oxygen diving at depth. Understanding these limits is not optional at this level, it is the foundation of every gas planning decision you make.

Gas Planning, Dive Tables, and Computers

Planning a dive with gases above 40% oxygen requires different calculations than standard nitrox planning. The course covers oxygen limit tables, dive computer use for high-O2 mixes, planning oxygen exposure across multiple dives in a day, and managing both oxygen and nitrogen limits simultaneously. Gas planning at this level is deliberate and specific, not a ballpark estimate based on a color-coded chart.

Equipment, Cylinder Labeling, and Gas Blending

Gases above 40% oxygen require oxygen-clean and oxygen-compatible equipment. Standard recreational gear is not rated for high-O2 mixes. The course covers which equipment is required, how to identify oxygen service ratings on cylinders and regulators, proper cylinder labeling for nitrox mixes above 40%, how to analyze a gas mix before a dive, and an introduction to gas blending procedures. These are not administrative details, using the wrong equipment with high-O2 gases creates a real fire and combustion risk.

In-Water Skills

The course includes open water dives. Required skill demonstrations include:

• Buoyancy control: holding a fixed position in the water column without moving hands or feet
• Team awareness: demonstrating communication, proximity management, and team-oriented dive practices with your buddy
• Primary regulator free-flow management: controlling a free-flowing regulator, executing a shut-down cycle, and switching to backup in a controlled manner
• Safety stop execution while maintaining neutral buoyancy
• Air sharing: acting as both donor and recipient while maintaining position in the water column
• Trim: demonstrating correct horizontal, streamlined body position while moving forward
• Stress analysis: demonstrating proper assessment of stress in yourself and your buddy

What Advanced Nitrox Unlocks

Completing TDI Advanced Nitrox qualifies you to:

• Dive using any gas mix from EAN 21 through 100% oxygen on no-decompression dives to 130 feet (40 metres)
• Enroll in TDI Decompression Procedures
• Enroll in TDI Semi-Closed Rebreather courses
• Enroll in TDI Closed-Circuit Rebreather courses

For most divers, Advanced Nitrox and Decompression Procedures are taught together. The two courses complement each other directly and together represent the standard entry point into technical diving. Call us at (480) 881-4013 if you want to discuss doing both in the same program.

Who Can Enroll

The TDI Advanced Nitrox course is open to certified TDI Nitrox Divers or equivalent. Additional requirements:

• Minimum age 15 with parental consent, 18 without
• Proof of 25 logged open water dives

Gear and Equipment

Students are required to own their own mask, fins, boots, and snorkel. Technical diving gear for this course, including oxygen-compatible cylinders, regulators, and BCDs, is available through Dive Arizona. That said, diving with high-O2 gases on gear you own, know, and have had oxygen-serviced yourself is the right approach at this level. Divers who train on their own equipment are better prepared for everything that follows in the technical track. If you need to put together a technical gear setup before this course, stop by the shop and we will help you spec it out. All students enrolled in a course receive a discount on purchases during enrollment.

Frequently Asked Questions

What is TDI Advanced Nitrox?

TDI Advanced Nitrox is the certification that qualifies divers to use enriched air nitrox from EAN 21 through 100% oxygen on no-decompression dives to a maximum depth of 130 feet (40 metres). It covers the physics and physiology of high-oxygen mixes, oxygen and nitrogen exposure limits, gas planning, equipment requirements for gases above 40% oxygen, cylinder labeling, gas analysis, and an introduction to gas blending. It is also the prerequisite for TDI Decompression Procedures and for semi-closed and closed-circuit rebreather training.

What is the difference between TDI Nitrox and TDI Advanced Nitrox?

Standard TDI Nitrox covers enriched air mixes up to 40% oxygen for recreational no-decompression diving. TDI Advanced Nitrox covers everything above that threshold, gas mixes up to 100% oxygen, the physiology of oxygen toxicity at higher percentages, oxygen exposure limit tracking, and the equipment requirements specific to high-O2 gases. Advanced Nitrox is also the gateway to the full TDI technical diving track.

What oxygen percentage can I dive after Advanced Nitrox?

After completing TDI Advanced Nitrox, you are qualified to use gas mixes from EAN 21 through 100% oxygen on no-decompression dives to a maximum depth of 130 feet (40 metres). Dives requiring staged decompression require TDI Decompression Procedures certification.

What courses does Advanced Nitrox unlock?

TDI Advanced Nitrox is the prerequisite for TDI Decompression Procedures, TDI Semi-Closed Rebreather, and TDI Closed-Circuit Rebreather courses. Most divers pursuing the full technical track do Advanced Nitrox and Decompression Procedures together -- call us at (480) 881-4013 if you want to discuss combining both into one program.

Do I need special gear for the TDI Advanced Nitrox course?

Yes. Gas mixes above 40% oxygen require oxygen-clean and oxygen-compatible equipment. Standard recreational rental gear is not rated for high-O2 mixes. Dive Arizona has compatible gear available for the course, but ownership is strongly encouraged -- divers who train on their own equipment are better prepared for the technical track ahead. Stop by the shop and we can help you put together the right setup.

Can Advanced Nitrox be taught with Decompression Procedures?

Yes, and it often is. The two courses complement each other directly, Advanced Nitrox covers the gas knowledge and physiology, while Decompression Procedures covers planned deco diving. Together they are the standard entry point into technical diving. Call us at (480) 881-4013 to discuss scheduling both.

Ready to Go Beyond 40%?

Contact us to schedule the TDI Advanced Nitrox course. Call us at (480) 881-4013 or stop by the shop. We are open Monday through Saturday 11am to 6pm and Sunday 11am to 5pm, at 18618 S 186th Way, Queen Creek, inside The Shooting Range.

For more information and to see course standards, click here!