Extended range
Deco stop at Cenote the Pit Dos Ojos

The TDI Extended Range course teaches you the proper techniques to efficiently use compressed air as a bottom gas to a maximum depth of 55 meters / 180 feet. Some parts of the world offer spectacular dives at depths greater than 39 meters / 130 feet, but helium is not accessible (or very limited). Extended Range training provides knowledge of equipment requirements and the dangers of deep diving requiring nitrox or oxygen decompression stops.

Dives not to miss!


  • Spectacular dives deeper than 39 meters/130 feet
  • No access to helium
  • Learn the proper techniques for safely using compressed air as a breathing gas
  • Staged decompression (with nitrox or oxygen)
  • Maximum depth of 55 meters/180 feet

Course prerequisites

What you will learn during your extended range training

  • History of deep air diving
  • Physics
  • Physiology
  • Decompression Options (Air, Nitrox, Oxygen)
  • Equipment considerations
  • Dive planning
  • Technical dive support
  • Navigation

In water skills

  • Use START before every dive
  • Stress analysis and mitigation
  • Gas matching procedures
  • Demonstrate buoyancy control
  • Good awareness, communications, proximity, and team-oriented dive practices
  • Manage 2 stage cylinders,
  • Gas switches
  • Lift bag deployment
  • Air-sharing ascent
  • Contingency decompression schedule
  • Remove and replace mask, deploy back up mask
  • Tired diver tow
  • Breath-hold swim
  • Execute the planned dive
  • Switching and isolating a malfunctioning regulator,
  • Navigational techniques
  • Ascent with ascent reel and lift bag and perform staged decompression
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