Diving into Perth’s Underwater World: Exploring Ammo Jetty

Tucked away on the coastline just south of Fremantle lies one of Perth’s best

shore dives—Ammo Jetty. From the surface, it may not look like much: a long, weathered structure stretching into the Indian Ocean, frequented by fishermen and seabirds. But slip beneath the surface, and a whole different world reveals itself—bursting with color, teeming with life, and pulsing with the calm rhythm of the sea.

It had been six long months since my last dive—six months since arriving in Perth, dry and slightly restless. After spending an entire year living, breathing, and working in scuba, the sudden stillness felt unnatural. My gear had been tucked away for far too long, and I was itching to get back beneath the surface. What better way to ease back into the water than with a cheeky little shore dive?

The morning started off slow. We’d taken too long to get out of bed, then spent even longer sorting out a rental car so we could actually get ourselves—and all our gear—down to the jetty. After that, it was a bit of a mission finding a dive shop that was open and had tanks available. One of those days where everything feels just a little out of sync.

We ended up finding a dive shop called Perth Scuba, and they set us up with tanks for just 20 AUD each—which felt like a steal compared to prices we’d paid elsewhere. The guy working the front desk was incredibly helpful and more than happy to share some local knowledge. He gave us a handful of tips about diving around Perth and what we might spot at Ammo Jetty—mentioning everything from octopus to the occasional seahorse if we looked closely enough.

He also gave us a quick rundown on safety, the main thing being to watch out for fishing line, since the jetty is a popular spot for both divers and anglers. A fair warning, and something we kept in mind as we packed our gear and made our

way to the site.

Even with the sluggish start, I could feel the familiar excitement building. The moment we had everything packed—tanks secured, wetsuits thrown in the back, and the faint smell of neoprene filling the car—I knew the wait was going to be worth it. Ammo Jetty was calling.

We made our way over to Ammo Jetty, found a spot to park, and started gearing up. After a quick buddy check, we were off toward the water. Honestly, the walk from the car to the jetty was probably the worst part. It wasn’t particularly long, but it was just far enough to get uncomfortably warm in our wetsuits—not ideal when you're already eager to cool off underwater.

Entry was straightforward—a casual stroll into the ocean from the sandy beach just beside the jetty. The swell was minimal, which made for a relaxed entry and an easy descent as we moved deeper.

Once we were under, we slowly made our way beneath the jetty. It was a bit choppy in the shallows, but the moment we got further in and a little deeper, everything settled. The movement of the water quieted, and the structure of the jetty above created this beautiful cathedral-like canopy, teeming with marine life.

The water was on the colder side—19°C. Not unbearable in a 7mm wetsuit, but by the 60-minute mark, I was definitely feeling it. I started to shiver and knew it was probably time to think about wrapping up.

With a max depth of only about 7 meters, we were able to stay down for a long time without burning through our air. That kind of depth is perfect for just cruising and observing without needing to stress about air consumption or bottom time.

Underneath the jetty was absolutely teeming with life—far more than I’d expected, honestly. We were surrounded by schools of curious fish, many of which I’d never seen before. Each pillar holding up the jetty was like its own mini reef, layered with seaweed, sponges, and marine growth that had turned them into vertical gardens of color and texture.

Among the nooks and crannies, we spotted all kinds of critters—tiny crabs scuttling between shadows, huge, chunky nudibranchs creeping along the beams, and the undisputed king of the jetty: a massive resident octopus. He had made himself a little kingdom, nestled in a throne built from discarded shells and fish bones. He watched us with calm, calculating eyes, clearly used to divers passing through his domain.

But the highlight of the dive? Four vibrant orange seahorses, clinging to the seaweed like ornaments. They were much larger than I expected seahorses to be, and watching them sway gently with the current was nothing short of magical. It felt like stumbling into a hidden world—one that had been quietly thriving just beneath the surface all along.