This is where technical diving gets genuinely serious, and genuinely exciting. Tec 40 Trimix is your doorway into helium-based diving, extending recreational Tec 40 to include trimix, a blended mix that manages narcosis and oxygen exposure on deeper dives. Over two days you'll work through knowledge development, practical sessions and four training dives, coming away able to plan limited-decompression dives to 40 metres using up to 50 percent oxygen.

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In detail

About This Course

Tec 40 Trimix is the doorway into helium-based technical diving, extending the skills of the recreational Tec 40 program to include trimix, a blend of oxygen, nitrogen and helium used to manage narcosis and oxygen exposure on deeper technical dives. It is designed for confident, experienced divers ready to formalise their gas planning and decompression procedures.

The course is built around seven knowledge development sections covering trimix theory, dive planning, equipment configuration and decompression procedures, paired with four practical application sessions where you rehearse skills and procedures before taking them into open water. Four training dives then let you put the full package together under real conditions.

You will learn to plan and execute limited-decompression dives to 40 metres, using up to 50 percent oxygen as a decompression gas to accelerate off-gassing safely. Gas management, redundant equipment configuration and structured team procedures all get significant attention, reflecting the more considered, planned approach that technical diving demands compared with recreational diving.

Because it sits early in the TecRec pathway, Tec 40 Trimix is as much about building disciplined habits as it is about depth. Get comfortable here and the step up to Tec 45 becomes a natural progression rather than a leap.

The process

How The Course Works

Step 1
Trimix Theory
You extend your Tec 40 gas planning knowledge to include helium, learning how blending it into your mix reduces narcosis and keeps you clear-headed on deeper technical dives. It is a small addition to the syllabus that changes how the whole dive feels.
Step 2
Trimix Training Dives
You then complete a portion of your training dives breathing a helium-based blend, analysing your own gas and adjusting your planning accordingly. It is the same Tec 40 depth range, just reached with a clearer head and a broader toolkit.
Reported structure: dives conducted on a normoxic trimix blend of at least 21% oxygen and up to 35% helium

Course curriculum

What You'll Learn

Learning Outcomes

limited decompression dives to 40m/130ft
use up to 50 percent oxygen as a decompression gas
tec diving procedures and gas management basics

Getting ready

Before You Start & What's Next

What's Included

seven knowledge development sections
four practical application sessions
four training dives

Prerequisites

PADI Advanced Open Water Diver (PADI Rescue Diver recommended)
PADI Enriched Air Diver
PADI Deep Diver or proof of 10 dives to 30m/100ft or deeper
minimum 30 logged dives
at least 18 years old
Diver Medical Form signed by a physician within the last 12 months

Next Steps

Tec 45

Upcoming training

Dates & Booking

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Quick facts

Duration

2 days of structured training

Location

Unit 4, Bellman Court, Great Knollys Street, Reading, RG1 7HD

Certification

Recognised PADI qualification on completion

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Tec 40 Trimix

What to expect