In diving, a surface interval is the time you spend out of the water between dives. You rest. You let your body off-gas. You eat something, maybe have a drink, watch the water. Then you go back down.

Mine has lasted about thirty years.

I got into diving through a university mate who introduced me to an instructor called Jack. That introduction changed the next five years of my life more than anything else that happened at university. Jack was one of the toughest men I've ever met — rough upbringing, no softness to him on the surface — but underwater he was a different kind of person. Patient. Precise. Genuinely in love with what he was showing people. He had more enthusiasm for a first-time student's first shark sighting than most people manage for anything.

We dove together most weekends. We drank together after. Nobody loved a cold pint more than Jack, and he'd earned every one of them. Over two or three years we became close friends, the way you do when you share something that takes real trust. He's gone now. I think about him every time the subject of diving comes up.

Julian Rocks and the art of jumping into nothing

The first proper dives were training dives in the Tweed River. Controlled. Murky. Exactly what you'd expect from a stretch of river water. Fine for learning, not much to look at.

Then came Julian Rocks, just off Byron Bay. That was different.

Julian Rocks has a particular trick it plays on divers. The surface visibility is often close to zero — green soup, no depth, nothing to see. You stand on the boat and look down and there's genuinely nothing there. Student divers freeze. Divers who learned on the clear northern waters of the Barrier Reef sometimes won't get off the boat at all. I watched groups of tourists from Asia, experienced divers, take one look at that water and decide they'd rather stay dry.

The thing is, once you descend, everything changes. Below the murk the water opens up. On a good day the visibility improves as you go deeper, which is the opposite of what most people expect. The shadows resolve into shapes. The shapes become fish. The fish become a reef system that has no interest in what the surface looks like.

That gap between what the surface promises and what's actually down there — that's diving, really. You have to be willing to jump into the nothing to find out what's underneath it.

The reef doesn't care what the surface looks like. Neither should you.

The first reef

Lady Elliot Island sits at the southern tip of the Great Barrier Reef. It was my first real reef dive, and nothing about the previous months of training had prepared me for the scale of it.

We had a group with us that trip that included some Norwegian divers who'd spent years doing cave diving in Europe. Technically accomplished, genuinely experienced. One of them said, wading out through the shallows toward the drop-off, that he'd already seen more fish than in three years of cave diving. He wasn't exaggerating to be polite. He was just stating a fact with the slightly dazed look of someone recalibrating.

The drop-off at Lady Elliot falls away fast. One moment you're in ten metres of water with coral below you, the next the bottom disappears and you're floating above open blue with no floor visible. That first time, it takes your breath — which is a problem when you're breathing from a tank and need to manage your air. You learn quickly to keep your composure and look around slowly. There's always something worth the patience.

The night dives were something else again. Twenty, thirty metres down on the reef, moonlight filtering through the water from above, enough ambient light that you could see the bottom without a torch if the moon was right. A school of manta rays hovering over the coral, perfectly still, being cleaned by small wrasses working the edges of their wings. The mantas weren't going anywhere. They had nothing to fear and nothing to chase. They were just there, in the dark, letting the smaller fish do their work.

I've thought about that image a lot in the thirty years since. There's something about the scale and the stillness of it that doesn't compress into words particularly well. It just stays with you as a sense of having been somewhere that operated on completely different terms to the surface world.

Wrecks and tight spaces

Wreck diving was always a treat, with one caveat: I was never comfortable in tight spaces. There's a particular kind of diver who loves threading through a ship's interior thirty metres from fresh air, navigating corridors that haven't seen daylight in decades. I understood the appeal intellectually and had absolutely no desire to do it myself.

The outside of a wreck is a different matter entirely. Wrecks become artificial reefs within years of going down. The structure attracts fish, the fish attract bigger fish, the whole system builds around a shape that was never meant to be there. There's something strange and satisfying about swimming along the hull of a vessel that was built to be on top of the water, now home to a hundred things that have no idea what a ship is.

Jack worked out of Cairns for a period. His particular speciality up there was tiger shark feeding — taking tourists down and hand-feeding tigers that had learned to associate the dive boats with a meal. This was the kind of thing that was done differently then, and there are reasonable arguments about whether it should be done at all. But watching Jack with those sharks said everything about the man. Completely calm. Completely in control. Treating an apex predator like a large and somewhat demanding golden retriever. The sharks knew him. That was the part that stayed with me.

What the reef has been doing without me

I stopped diving when the kids arrived. Weekends became junior sport and school commitments and the hundred things that fill up the years when your children are young. The tanks stayed dry. That's just how it went.

The news about the reef since then has been difficult to read at times. Bleaching events. Coral loss. Reports about what climate change is doing to water temperatures and what that does to the coral. None of it is easy to sit with if you've spent real time down there.

Here's what I actually think, having been in that water and visited sites after major events: the reef is tougher than the coverage gives it credit for, and most people writing about it have never been below the surface. That's not a political statement. It's just a fact about who gets quoted.

I was at Lady Musgrave Island not long after a cyclone had come through. The bommies — the coral heads that rise from the sandy bottom and act as the anchors for whole ecosystems — had been broken up and scattered. It looked wrecked. Genuinely wrecked. Then you looked around and the fish were still there, the water was still clear, and not far away there was a section the cyclone had left alone entirely. The reef wasn't recovering. It had simply continued, in the places the cyclone hadn't reached, as if nothing had happened.

When one place is down, somewhere else is shining. The reef has been running that logic for longer than anything we've built has existed. I'm not saying the damage isn't real. I'm saying the obituary gets written too early, by people who've only ever seen it from a boat.

What I'd go back to find

If I went back tomorrow, some things would be completely new to me. Rebreather technology has changed what's possible underwater — closed-circuit systems that recycle your breathing gas, extending bottom time dramatically and eliminating the bubble trail that alerts marine life to your presence. Mixed gas diving that lets you go deeper and stay longer with less risk, if you know what you're doing. When I was diving, these were either experimental or the exclusive territory of technical divers with serious training and serious budgets. Now they're accessible in a way they weren't.

That genuinely fascinates me. More time underwater, quieter presence, deeper access. The technology has caught up to what divers always wanted.

But the thing I'd go back to find hasn't changed and doesn't need technology. It's the peace of it. The scale. The complete absence of anything that wants something from you. Underwater, nothing needs a response. Nothing is urgent. The reef is just there, doing what it's been doing, indifferent to everything above the surface.

That's the pint of view you can't get any other way.

★

Jack would have had opinions about rebreathers. He'd have read everything, argued about the risks, probably learned to use one himself just to know what he was talking about. He'd have been on the reef until he physically couldn't be, because that's what he loved and he never needed a reason beyond that.

I think about that more than I probably should.