IANTD Normoxic Trimix Plus Diver Course in Mexico
Progress toward deeper Trimix diving with mandatory decompression to a maximum training depth of 75 metres / 245 feet with the IANTD Normoxic Trimix Plus Diver course.
Designed for divers already certified as Normoxic Trimix Divers, this advanced program develops the use of helium, deep-dive planning and the management of two decompression gases.
✔ Advanced Trimix training to a maximum of 75 metres / 245 feet
✔ Two decompression gases
✔ Manifolded doubles or technical sidemount configuration
✔ Training with an IANTD Normoxic Trimix Instructor
✔ Available in English, French or Spanish
Normoxic Trimix Plus Course: Essential Information
Certification: IANTD Normoxic Trimix Plus Diver
Prerequisite: Normoxic Trimix Diver or equivalent
Maximum depth: 75 metres / 245 feet
Minimum number of dives: 2
Minimum runtime: 110 minutes
Confined-water session: 1
Dive between 63 and 75 metres: minimum 1
Decompression gases: 2 required
Configuration: manifolded doubles or technical sidemount
Mandatory decompression: yes
Price: from MXN 5,000 per day
Languages: English, French or Spanish
The maximum depth is a training limit, not an objective that must be reached regardless of conditions or demonstrated skills.
What Is the IANTD Normoxic Trimix Plus Diver Course?

The IANTD Normoxic Trimix Plus Diver course is a progression program designed for divers who are already certified as Normoxic Trimix Divers.
It develops the knowledge and procedures required to independently plan and conduct Trimix dives with mandatory decompression to a maximum depth of 75 metres / 245 feet.
Using a breathing mixture containing helium helps control the effects of narcosis and gas density during deeper dives.
The program further develops:
- bottom-gas selection;
- decompression planning;
- use of two decompression gases;
- reserve-gas management;
- gas switches;
- teamwork;
- emergency procedures;
- contingency planning.
Who Is This Trimix Course For?

This course is designed for experienced technical divers who want to:
- progress beyond the limits of Normoxic Trimix Diver;
- conduct Trimix dives to a maximum depth of 75 metres;
- use two decompression gases;
- improve deep-dive planning;
- better control narcosis;
- manage more significant decompression profiles;
- refine their technical equipment configuration;
- develop greater autonomy and stronger team procedures;
- prepare for future progression toward Trimix Diver.
This is not an entry-level Trimix course.
Candidates must already possess the knowledge, experience and practical skills developed at the Normoxic Trimix Diver level.
Normoxic Trimix Plus Course Prerequisites
According to the IANTD standards used for this program, candidates must:
- hold an IANTD Normoxic Trimix Diver certification;
- or hold an equivalent or higher certification;
- be proficient with a redundant technical-diving configuration;
- have recent Trimix-diving experience;
- be capable of using two decompression cylinders;
- demonstrate buoyancy and trim appropriate for deep technical diving.
Your dive log, certifications and recent experience are reviewed before the program is confirmed.
An evaluation dive may be recommended when your equipment configuration or mastery of the required procedures needs to be assessed.
Course Objectives
The objective of the program is to develop your ability to plan and conduct Trimix dives with mandatory decompression to a maximum depth of 75 metres.
You will learn how to:
- select an appropriate Trimix mixture;
- analyze and identify breathing gases;
- calculate maximum operating depth;
- determine equivalent narcotic depth;
- manage gas density;
- plan team gas consumption;
- calculate the required reserves;
- select two decompression gases;
- plan an ascent involving multiple decompression stops;
- organize gas switches;
- manage the loss of a decompression gas;
- adapt decompression to an unexpected situation;
- apply oxygen-exposure limits;
- manage a regulator failure;
- perform gas-sharing procedures;
- maintain team cohesion;
- respond to an emergency at depth.
Normoxic Trimix Plus Course Structure
The Normoxic Trimix Plus program is a relatively short but demanding progression.
Skills from the previous level must already be mastered.
Theory and Dive Planning
Theory sessions cover topics including:
- selection of Trimix mixtures;
- effects of narcosis;
- gas density;
- oxygen partial pressure;
- gas planning;
- deep decompression;
- selection of decompression gases;
- bailout strategies;
- contingency plans;
- loss of a breathing gas;
- team procedures;
- incident management.
You will actively participate in preparing the dive profiles and must be able to explain the decisions made during planning.
Confined-Water Session
A confined-water session is used to evaluate:
- equipment configuration;
- buoyancy;
- trim;
- valve shutdowns;
- gas sharing;
- cylinder handling;
- gas switches;
- SMB deployment;
- responses to major equipment failures;
- team communication.
This session allows any equipment or procedural issues to be corrected before the deeper dives.
Open-Water Training Dives
According to the IANTD standards used for the progression from Normoxic Trimix to Normoxic Trimix Plus, the program includes:
- two open-water dives;
- a minimum of 110 minutes of runtime;
- at least one dive between 63 and 75 metres / 207 and 245 feet;
- a minimum of 55 minutes of runtime on an additional dive;
- two decompression gases;
- mandatory decompression.
The final depth and dive profile depend on conditions, available breathing gases and the skills demonstrated during training.
Using Trimix to a Maximum Depth of 75 Metres
The bottom mixture is selected according to the maximum planned depth.
The IANTD standards used for this program specify the following limits.
For a Dive to 60 Metres
- minimum oxygen fraction of 19%;
- maximum PPO₂ of 1.4 during the active portion of the dive.
For a Dive to 75 Metres
- minimum oxygen fraction of 16%;
- maximum PPO₂ of 1.44 during the active portion of the dive.
The mixture must also contain an appropriate amount of helium according to the planned depth, acceptable narcosis and desired breathing-gas density.
These values represent program limits.
The final breathing mixture is selected according to the actual dive profile being planned.
Two Decompression Gases Are Required
Every dive in the program must be conducted with two decompression gases.
You must demonstrate the ability to:
- analyze each mixture;
- verify cylinder labels;
- calculate maximum operating depths;
- correctly position the cylinders;
- identify each breathing gas;
- perform gas switches;
- verify gas switches within the team;
- manage the loss of one decompression gas;
- adapt the decompression plan;
- maintain stable depth while performing procedures.
Using multiple gases provides additional decompression options, but it also requires strict discipline to prevent breathing an inappropriate mixture at the wrong depth.
Equipment Configuration Used During Training
The course can be completed using:
- manifolded doubles;
- a technical sidemount configuration.
Each diver must also carry two decompression cylinders containing sufficient gas for the planned profile.
The configuration must provide:
- effective access to the valves;
- complete redundancy;
- clear regulator identification;
- controlled cylinder handling;
- effective gas sharing;
- stable trim;
- management of equipment failures at depth;
- an ascent involving multiple gas switches.
Your equipment is inspected before the program begins.
Any necessary modifications must be completed before the deeper training dives.
Skills Developed During the Course
The course further develops:
- gas planning;
- RMV calculations;
- gas matching;
- decompression planning;
- gas switches;
- valve shutdowns;
- management of a free-flowing regulator;
- loss of a decompression gas;
- gas sharing;
- swimming while sharing gas;
- removing and replacing a cylinder;
- SMB deployment;
- stability during decompression stops;
- communication;
- teamwork;
- problem solving;
- decision-making at depth.
Procedures must be performed while maintaining buoyancy, trim and team awareness appropriate for this level of training.
Normoxic Trimix Diver vs Normoxic Trimix Plus Diver
Normoxic Trimix Diver
This course allows divers to conduct Trimix dives with mandatory decompression to a maximum depth of 60 metres / 200 feet.
Normoxic Trimix Plus Diver
This progression extends the maximum depth to 75 metres / 245 feet and further develops:
- selection of deeper breathing mixtures;
- management of two decompression gases;
- more demanding dive profiles;
- reserve-gas planning;
- emergency procedures;
- decision-making at depth.
Normoxic Trimix Plus therefore does not replace Normoxic Trimix Diver.
It is the next step in the progression.
What Comes After Normoxic Trimix Plus?
After certification and after developing sufficient experience, progression toward the IANTD Trimix Diver program may be considered.
Trimix Diver progresses beyond the Normoxic Trimix Plus level and involves:
- greater depths;
- increased autonomy;
- three decompression cylinders;
- more complex planning;
- significant experience with dives between 42 and 60 metres.
This progression should only be considered after consolidating your skills and gaining meaningful experience at the Normoxic Trimix Plus level.
Why Take Your Normoxic Trimix Plus Course in Mexico?
Playa del Carmen and the Riviera Maya provide access to different sites suitable for deep technical-diving training.
Site selection depends on:
- required depth;
- planned profile;
- weather conditions;
- breathing-gas logistics;
- diver experience;
- objectives of each training session.
The course may require specific travel to dive sites where the required depths can be reached under appropriate conditions.
The final program is confirmed after reviewing weather conditions, logistics and available breathing-gas mixtures.
Why Choose Halocline Explorers?
IANTD Normoxic Trimix Instructor
Your training is conducted by Julien Garnier, IANTD Instructor Trainer and Normoxic Trimix Instructor.
Small Groups
Participant numbers are deliberately limited to facilitate supervision and maintain a cohesive technical-diving team.
Training in Three Languages
The course can be taught in English, French or Spanish.
Personalized Planning
Every dive profile is adapted to your experience, equipment configuration and actual conditions.
Skills-Based Certification
Completing the minimum number of dives does not automatically guarantee certification.
Candidates must demonstrate mastery of the knowledge, planning and practical procedures required by the program.

Normoxic Trimix Plus Course Price
From MXN 5,000 per Day
The final price depends on factors including:
- number of training days required;
- Trimix mixtures;
- quantity of helium used;
- two decompression gases;
- cylinders required;
- available equipment;
- dive-site access fees;
- training and certification fees;
- travel required to reach suitable dive sites.
A detailed quote is prepared before the program is confirmed.
Frequently Asked Questions About the Normoxic Trimix Plus Diver Course
What Is the Main Prerequisite?
You must hold an IANTD Normoxic Trimix Diver certification or an equivalent or higher certification.
Can I Start Directly with Normoxic Trimix Plus?
No.
This program is a progression designed for divers who are already certified as Normoxic Trimix Divers.
What Is the Maximum Depth?
The maximum depth specified by the standards used for this program is 75 metres / 245 feet.
How Many Dives Are Required?
The progression includes at least two open-water dives and 110 minutes of runtime.
Does One of the Dives Have to Reach 75 Metres?
No.
At least one dive must be conducted between 63 and 75 metres.
The exact depth depends on the dive plan, conditions and demonstrated skills.
How Many Decompression Gases Are Used?
Two decompression gases are required on all dives in the program.
Can I Take the Course in Sidemount?
Yes.
The program can be completed using either manifolded doubles or a technical sidemount configuration.
Is Helium Required?
Yes.
The program involves the use of Trimix breathing mixtures containing helium.
Can the Course Be Completed in the Cenotes?
Site selection depends on available depths, conditions and training objectives.
Some dives may be organized at suitable deep sites, but this certification is not a cave-diving course.
Does the Certification Allow Me to Dive to 85 Metres?
No.
According to the IANTD standards version 26.2.0 referenced by your course documentation, the maximum depth for Normoxic Trimix Plus Diver is 75 metres / 245 feet.
Is Certification Guaranteed?
No.
Certification is awarded after successful validation of the required knowledge, planning and practical skills.
Can I Take the Course in English?
Yes.
The complete program can be taught in English, French or Spanish.
Ready to Become a Normoxic Trimix Plus Diver?
This course allows you to progress toward Trimix dives to a maximum depth of 75 metres / 245 feet, using two decompression gases and dive planning adapted to deeper technical profiles.
To receive a personalized training program, send us:
- your current certifications;
- Normoxic Trimix experience;
- number of technical dives;
- recent dives between 40 and 60 metres;
- current equipment configuration;
- training objectives;
- travel dates in Mexico.
