Most visitors know the South West by what sits on top of it: the surf breaks, the vineyards, the tall karri and the long line of the coast. Fewer look down. Run a finger along the map from Busselton to Augusta and you are tracing the Leeuwin-Naturaliste Ridge, a spine of ancient limestone that hides one of the richest cave systems in the country. There are hundreds of them beneath the ridge, and a handful have been opened, lit and made walkable, so that anyone can spend an hour in a world that took the water half a million years to carve.

This guide covers the four show caves worth building a day around, in order down the ridge, each measured by drive time from Abbey Beach Resort so you know exactly what a morning or an afternoon underground will cost you in road time. It also makes the case for going in the cooler months, when the weather above ground gives you every reason to head below it.

A cave keeps its own weather. Whatever the sky is doing, it is mild and still down there.

The Ground BelowWhy This Is Cave Country

The ridge is old dune limestone, laid down over a vast stretch of time and then slowly dissolved by rainwater seeping through it. Where the water found a weakness it hollowed out chambers, and where it dripped and evaporated it left minerals behind, one thin layer at a time. That is the whole quiet drama of a cave: stalactites reaching down from the ceiling, stalagmites rising to meet them, delicate straws, shawls and flowstone, all of it built at the pace of a few centimetres a century. Some of what you will see began forming before the first people walked this coast, and the local Wardandi Noongar people have known and named these places for a very long time.

Four caves along the ridge are set up for visitors, and they are genuinely different from one another rather than four versions of the same walk. One is a self-guided ramble, one is a deep bowl in the forest with a lake at the bottom, and two are grand, guided set pieces. Done as a loop, they make one of the best all-weather days the region has.

Cave 01 · YallingupNgilgi Cave, the Closest

Start with the one nearest home. Ngilgi is the most accessible of the four from the resort, and the oldest in visitor terms, having been shown to travellers since the turn of the last century. It carries a Wardandi story too, of the good spirit Ngilgi who drove an evil spirit from the cave, and that sense of a place with its own history sits well with the formations.

Cave 02 · Caves RoadMammoth Cave, at Your Own Pace

South of Margaret River town, three caves sit within a few minutes of one another on Caves Road, and this is where a proper cave day earns its name. First of the trio is Mammoth, the easy-going one, and the pick for families and anyone who would rather not be tied to a tour time.

Cave 03 · Caves RoadLake Cave, the Hidden Bowl

A few minutes on from Mammoth, Lake Cave is the most dramatic arrival of the four. Before you even reach the cave, you walk down into a deep collapsed sinkhole ringed with karri and peppermint trees, a green amphitheatre that most people were not expecting. The cave opens at the bottom of it.

Cave 04 · AugustaJewel Cave, the Grand Finale

At the southern end of the ridge, near where the Blackwood River meets the sea at Augusta, Jewel is the biggest and most ornate of the show caves, and a fitting place to finish. If Ngilgi is the friendly local and Mammoth the easy stroll, Jewel is the showpiece.

The PracticalitiesDoing the Caves Properly

A little planning turns four separate stops into one smooth day. Here is how to make it easy on yourself.

What to Wear and Bring

Caves are cool and can be damp underfoot, so wear closed shoes with grip and take a light jacket even in summer. There are a lot of steps in Lake and Jewel, so pack water and go at your own speed. A small torch adds nothing at the show caves, which are lit, but the formations photograph beautifully in the low light if you steady your phone or camera.

Tickets and Passes

The caves are run in two groups, with Ngilgi managed separately from the Mammoth, Lake and Jewel trio further south. Multi-cave passes are available for the southern caves and are the sensible buy if you plan to see more than one, which most people do. Check the current tour times before you leave, especially outside the school holidays when guided departures can be less frequent.

Making It a Loop

The tidy way to do it from the resort is a single run down Caves Road: Ngilgi on the way if you have the appetite, then Mammoth, Lake and Jewel in sequence, with a cellar door or a bakery lunch worked in between. Two caves in a day is a comfortable pace with children; three is doable for the keen. Whatever you choose, you are back at Abbey Beach Resort by evening with the whole of Geographe Bay in front of you.

The SeasonWhy Winter Wins Underground

Here is the quiet secret of a cave: it does not care what the weather is doing. A show cave holds a mild, steady temperature all year, so the wet and windy South West days that keep you off the beach are precisely the days to go below it. Winter also thins the crowds, which means smaller tour groups and guides with more time to talk. Add a long lunch and an open fire at a cellar door on the way home, and a grey day on the coast becomes one of the best of the trip. If you would rather build the day around the resort itself, the heated indoor pool, sauna and two on-site restaurants make the coming-home half just as easy.