PADI Tec 45: The Next Step in Technical Diving

There's a particular moment in a lot of divers' progression where the recreational limits stop feeling like boundaries and start feeling like a ceiling. If you've been diving to 30 or 40 metres on air or nitrox for a while, wondering what's beyond that wall, chances are you've already had half an eye on technical diving. PADI Tec 45 is where that curiosity turns into a genuine skill set, and with the shorter days and quieter dive calendar of a British winter, December and January are actually a good time to start thinking seriously about it.

What Is PADI Tec 45?

PADI Tec 45 is the second course in PADI's core technical diving pathway, sitting between Tec 40 and Tec 50. It extends your no-decompression diving into planned decompression diving, taking you to a maximum depth of 45 metres using air or nitrox as your back gas, with a single stage of oxygen-enriched decompression gas. In plain terms, it's the course where you stop diving purely inside no-stop limits and start deliberately planning and executing staged decompression stops as part of the dive itself.

It builds directly on the skills introduced in Tec 40, adding a second decompression gas switch and slightly extending both depth and planned decompression obligation. If you've ever wondered what separates a confident deep diver from a properly trained technical diver, Tec 45 is where that distinction becomes concrete rather than theoretical.

Who Tec 45 Is For

This course suits divers who already hold Tec 40, or equivalent training we can cross over, who are comfortable in the water, and who want a genuine reason to dive deeper and longer than recreational limits allow. We see three types of diver book onto Tec 45 through our Tec 45 course page: wreck divers who keep finding the interesting parts of a site just out of recreational reach, cave and cavern-curious divers building toward full technical certification, and simply meticulous, gear-focused divers who enjoy the planning and precision technical diving demands.

It is not, frankly, for everyone, and that's fine. Tec 45 asks for genuine commitment, to buoyancy control, to gas management, and to a mindset where the dive plan is followed rather than improvised. If that appeals rather than alarms you, you're in the right place.

Prerequisites Before You Start

To join a Tec 45 course with us you'll need to be a certified PADI Tec 40 diver, or hold a qualifying certification from another training organisation that our instructors can assess, be at least 18 years old, and have logged the required technical and open water dives specified in the standards. We'll also want to see recent, comfortable diving in cold water and thicker exposure protection, since a lot of Tec 45 training in the UK happens in exactly those conditions.

Medically, you'll need a dive medical statement confirming fitness for the physical demands of technical diving, particularly given the equipment load and the physiological demands of planned decompression. If it's been a while since your last medical, get that sorted early so it doesn't hold up your start date.

A Typical Tec 45 Course With Us

We run Tec 45 as a mix of classroom and confined water preparation followed by open water training dives, usually at inland sites where we can control conditions and repeat skills without a boat schedule dictating the pace. A typical day starts with kit assembly and a full pre-dive check that takes noticeably longer than recreational diving, because you're now managing a stage cylinder, additional gas switches, and a more detailed dive plan.

Underwater, sessions focus on drills as much as depth: valve shutdowns, out-of-gas simulations while managing a stage cylinder, controlled ascents with staged decompression stops, and gas switch procedures practised until they're close to automatic. Debriefs after each dive are detailed, because in technical diving the small procedural details are exactly what keeps a dive safe.

What You Actually Learn

Gas Planning and Reserves

You'll learn to plan gas for the bottom phase and the decompression phase separately, build in genuine reserves for a buddy's gas failure, and calculate turn pressures that account for the extra work of managing decompression stops in current or cold water.

Decompression Procedures

This is the heart of the course: how to plan, execute, and adapt staged decompression using tables or planning software, how to manage a single decompression gas switch safely, and how to recognise and respond to problems during the ascent phase, when there's no longer the option of surfacing directly.

Equipment Configuration

You'll also come away with a proper technical equipment configuration, from stage cylinder rigging to backup instrumentation, set up in a way that's standardised and predictable rather than improvised.

Why Winter Is a Good Time to Start

There's a practical reason a lot of our Tec 45 candidates begin their classroom and confined water work in December and January rather than waiting for spring. The dive calendar is quieter, which means more flexibility on scheduling and more one-to-one time with an instructor rather than sharing attention across a packed group. It also means that by the time the better weather and longer daylight hours of spring arrive, you're already through the theory and confined water phases and ready to move straight into open water training dives without losing momentum.

If a Christmas gift voucher toward training is on your radar, either giving one or receiving one, technical diving is exactly the kind of goal that benefits from a concrete starting point like that. It turns a vague "I should get into tec diving" into a booked first session with a date attached to it.

Kit and Investment

One of the more common hesitations around Tec 45 is the assumption that you need a full technical equipment configuration before you even start. In practice, we provide stage cylinders and the specific technical kit needed for training, so your first course doesn't require a big upfront spend. Where investment does make sense is in a well-fitted drysuit and thermal undergarments if you're training through a UK winter, since comfort in cold water has a direct effect on how well you absorb everything else being taught.

Most divers who go on to Tec 50 and beyond do eventually build their own technical configuration, piece by piece, once they know exactly what suits their body position, their local diving, and the direction they want to take their training. There's no rush to get there before you've even done Tec 45.

Common Questions Before Booking

Do I need my own technical equipment? Not to start. We can provide stage cylinders and specific technical kit for training, though most divers who continue into Tec 50 and beyond invest in their own configuration fairly quickly.

How long does the course take? Most divers complete Tec 45 over several weekends or a concentrated week, depending on scheduling and how much confined water preparation they need.

Is it much harder than Tec 40? It's a meaningful step up, mainly because of the added decompression obligation and the second gas switch, but if you were comfortable in Tec 40 you have the right foundation.

What happens after Tec 45? Most divers move on to Tec 50, which extends depth and decompression obligation again, and from there toward trimix diving for those who want to keep progressing.

Can I train through the winter or should I wait for spring? Winter is genuinely a good time for the classroom and confined water phases, and many candidates complete their open water dives at inland sites where conditions are controllable year-round, so there's no need to wait.

Will this affect my recreational diving? If anything, most divers find their recreational diving improves afterward. The gas management, situational awareness, and precision required in technical training tend to carry over into every dive you do afterward, recreational or otherwise.

Why It's Worth Doing

Tec 45 isn't just a depth badge. It's the course where planned decompression diving stops being theoretical and becomes something you can execute calmly and correctly, which is exactly the skill set that opens up deeper wrecks, more interesting profiles, and a genuine pathway toward Tec 50 and full trimix diving further down the line. Whether you complete your training with us at Tec 45 or use it as a stepping stone into the wider Tec Academy pathway, it's a course that changes how you think about every dive afterward, recreational or technical.

Thinking about giving yourself, or a diver in your life, a proper technical challenge this year? Find out more about Tec 45 or get in touch to talk through where you are in your training - we're at Bellman Court, Great Knollys Street, Reading, or call +44 (0) 118 9761 729.