On Sunday we packed up and caught the local bus into the town centre. Pula has ping-ponged from empire to empire since the Romans, and there’s an impression of peeling off the skins of an onion as you travel in. You get Communist-era apartment blocks on the outskirts, petering out the further in you get, then baroque Austro-Hungarian façades, the odd angular Venetian edifice and finally, nestled among them all, scattered Roman monuments.

Our apartment was within spitting distance of the Arena, a mini-me colosseum parked on the edge of the town centre, and we wandered past it and around the circular Kandlerova Ulica which seems designed to entrap disorientated tourists in a never-ending parade of ice-cream parlours and shoe shops. James Joyce taught English here at the turn of the century (which might account for some of the indecipherable menu items) and at the end of Kandlerova we sat with his statue at Café Uliks for a spot of people watching. I came to the conclusion that Pula might only be a couple of miles north of Punta Verudela, but it’s about ten years ahead in sartorial terms.

I wanted to do some roman’ around the next day, so in the morning I took the camera and popped next door to the Arena. It’s certainly impressive that it’s still standing after a couple of millennia, but there was precious little context to all of it. I know next to nothing about the Romans (well, enough to feel slightly uneasy about the divers’ signal meaning ‘descend’) and there were no information boards or the like, so I snapped some pseudo-arty shots of the Adriatic framed by the colonnades and wandered back to pick up Ash. We duly saw the sights – the Cathedral, the Temple of Augustus, the Venetian fort on the hill in the centre of town – but none of them really caught my imagination, and not one of them deigned to explain anything about themselves. Odd.

Despite being underwhelmed by what should have been historic marvels and instead were just ordered piles of rocks, after a couple of days pottering around I felt thoroughly at home. There’s a nice bit of cheerfulness to the place (probably down to everyone getting plenty of vitamin B); it isn’t too crowded, and the ability to sit outside to eat, drink or read any time of the day made me think that maybe Joyce wasn’t far wrong in coming here for a while.*

* Actually, had he been staying in our apartment he’d probably have hated the damn place. The attic bedroom was too hot to sleep in, and downstairs the mosquitoes absolutely plagued us all night. In a delirious rage at about 4.30am, I swatted a particularly bloated one leaving a massive bloody streak against the wallpaper that I had to swab off with a kitchen towel. Urgh.

Ash, an out of practice rescue diver, had booked a refresher dive for the next morning, and after some discussion with (i.e. good-natured derisive snorting from) the attendant diving instructors, I was throwing caution and medical advice to wind and doing a beginner’s “discovery” dive after lunch. I hung around while Ash got kitted out, helped them lumber down into the shallows and watched with increasing surprise as they took a few experimental breaths and sank beneath the waves. It’s not that you don’t know that this is what happens, but to see your girlfriend disappear with the merest traces of bubbles left behind is rather unnerving. I half expected them all to come up for a big breath any second; they didn’t, so I took a seat among the barbequing sunbathers to wait for them.

After about forty minutes they surfaced again and I could tell Ash wasn’t all that impressed. Apparently, Marco the guide was disinterested and workmanlike, the house “reef” was mostly a pile of rocks and the fauna (listlessly prodded by Marco, which is apparently considered extremely bad form by PADI) was restricted to some hermit crabs and the odd starfish.

I had a different guide: a friendly Dutch guy called Patrick who was both enthusiastic and serious about diving. We did a half hour of theory, most of which seemed sensible to a lapsed physicist like your correspondent (main take-home tip: fail to breathe out as you ascend and your lungs will explode), along with a few signs meaning “OK”, “My ears hurt” and “It’s getting a bit tricky” among others. The gist of the dive itself was that he’d hold onto my left arm the whole time and also manage my buoyancy by inflating or deflating my BCD for me. All I had to do was to swim in the directions he indicated and try not to freak out.

I got into my wetsuit, complete with hilariously ripped ass seam, and waddled down the the stony beach. It’s not obvious when watching experienced divers, but in the shallows you’re about as mobile as a newborn baby. I floundered around like a beached whale trying to put my fins on, eventually coming to a vaguely composed halt by kneeling on a rock with Ash’s help while I waited for Patrick to get ready. “Put on your mask,” he said, “try out the regulator by sticking your face in the water.”

Here goes then, I thought. I put the regulator in my mouth and took a couple of exploratory breaths; it seemed fairly natural above water, although you do need to breathe in fairly emphatically to start the air flowing each time. I stuck my head in the water and lasted for about three breaths, reflexively jerking my head back out again exactly when a single lungful of air would have run out.

“OK?” asked Patrick.

“Yup!! It’s weird! It’s very weird,” I prattled. I didn’t know how to phrase “Good God, what the hell have I agreed to here?” such that it didn’t sound bad, so beyond that I kept my trap shut.

“You’ll be okay. Now what we’re going to do is we’re going to swim out to that pontoon” – he pointed to the edge of the floating pier, maybe ten metres away – “face down, with our jackets filled with air so we’re buoyant, then we’ll stop and dive to a sandy bowl about six metres down.”

I listened, mechanically put the regulator back in my mouth and swam with him over to the pier. With the air tanks on our backs we were mostly submerged and there was no way to avoid breathing entirely through the regulator. Through my mask I watched the sea bed slide past and drop away from us and the whole time (although it was only about thirty seconds) tried to ignore the part of my brain emitting a continuous silent scream. We got to the end of the pier and righted ourselves so we were bobbing vertically on the surface, the water rolling around at mask level. I snatched a couple of breaths of fresh air, not quite believing what we’d just done.

“OK?” the instructor signed.

“OK!!” I twitched back.

He pointed down with his thumb, indicating that we were about to dive, then deflated my BCD and his BCD in turn. We dropped slowly downwards and I concentrated very, very hard on swallowing to equalise the pressure in my ears while breathing as regularly as I could. The mental effort almost exactly balanced the urge to freak out, so that for that first descent I was teetering on the edge of a sort of existential rather than physical panic.

The number of different sensations is overwhelming: the effort needed to breathe through the regulator initially feels like shortness of breath, while the mouthpiece itself is pulled slightly to one side by the hose and threatens to come out if you relax your jaw for a second. The exhaled bubbles rush past your ears with a deafening roar, your inner ear snaps, crackles and pops as the pressure changes and the water swilling around the bottom of your mask makes it feel like something critical is leaking. Oh, and being completely submerged – not only that, but six metres below the surface – leads to utterly perfect cognitive dissonance. “Why am I not drowning?” your brain quite reasonably asks. “You’ve got me,” you reply. And there’s another curiosity: you can’t talk to your diving buddy, so all of your conversations are with yourself: the internal monologue becomes a dialogue.

“Holy crap, this is weird.”

“I know! You don’t have to tell me twice.”

We settled on the bottom in the patch of sand. Patrick inflated my BCD until I was more or less neutrally buoyant and motioned for me to swing up so I was horizontal, facing the sea floor; he did the same and we slowly kicked off.

I’d managed to wall off my incredulity by now and followed his lead as we swam forwards and down, popping my ears all the while. We pointed (with slightly disproportionate enthusiasm) at the fish and crustaceans we saw along the way.

“There! Could that be a herring?”

“My word! I do believe it is a veritable shoal of them.”

Stopping on the bottom again a few minutes later, he pointed at his depth gauge: 14.6m! As I looked up at the cloud of bubbles floating up to the barely visible surface, I had the thought that “I could just take the regulator out at any time,” in exactly the same way that when peering over the edge of, say, the Grand Canyon you might be inclined to think “it would be so easy to jump.” The fact the I didn’t immediately spit out the mouthpiece reassured me greatly.

Patrick gave me the thumbs up and we followed our bubbles to the surface, my ears crackling as they equalised themselves. We popped up on the other side of the floating pier, I ripped off my mask and, oddly worried that I might suddenly be unable to breathe, took out the regulator. “Well done!” he said, “that was about seventeen minutes, you’ve used about a third more oxygen than me and we got to 14.6 metres. How do you feel?”

“Intrigued,” was the best way I could put it. I don’t know if I could call it fun – I was too busy suppressing the urge to wig out most of the time – but it was such a novel experience that we’re already talking about a diving trip next year!

Update: Hooray! We remembered my instructor’s name, and it is Patrick.

Turns out there are no hotels near Stansted; at least, none costing less than £150 per night. With neither standby rates nor in fact any rooms available at the exorbitant inn, we spent a truly grim night on a plastic bench in Domestic Arrivals, kept awake – or rather, in a hideous semi-waking nightmare – by a hippie student arythmically banging a djembe so his compadres could practice capoeira into the small hours.

For the record, they were all crap at it.

We slept through the flight and woke up circling Pula International. The plane went from temperate to sauna as the doors opened and we ambled slowly across the scorching apron to the single gate. The airport is small, plain and refreshingly matter-of-fact: there are no airbridges, covered walkways, shuttles to the terminal or any of that jazz: if you get sucked into a jet engine then it’s your own fault for displaying such rank carelessness. We got on a ancient transfer coach (either it or the equally ancient driver had an inbuilt speed limit of about 40kph) and trundled to Pula bus station.

Our accommodation for the first few nights was south of Pula, in an area called Punta Verudela. Despite having booked everything months in advance, we were almost studiedly unprepared for everything after the transfer bus and it took us two hours of blistered feet, aimless wandering and constant whining from yours truly (I will never wear flip-flops again, I can tell you that much) until we finally collapsed, sweating and exhausted, in our ’70s apartment.