Mount Gambier sits on top of Australia’s most recent volcanic activity and is the last town on the Limestone Coast. The city is surrounded by crater lakes, riddled with sinkholes and flanked by a climbable volcano. I passed through on day three of my Limestone Coast road trip and saw two of its headline sights, the Blue Lake and the Umpherston Sinkhole, and both were amazing.
I arrived on Australia Day, and unfortunately the cafes were winding down their kitchens and my Mount Gambier lunch ended up being a service station sandwich before I pushed on to Port Fairy. So this guide covers what I saw first-hand, plus the sights I have since researched.
The Blue Lake and the Umpherston Sinkhole are Mount Gambier’s two highlight stops. Both of which can be seen in a couple of hours. With a full day, or an overnight, you can visit the caves, lookouts and the crater lakes.
Mount Gambier is the last major stop in South Australia on the drive from Adelaide towards the Great Ocean Road, around two hours from Port Fairy across the Victorian border. It also pairs with Mount Schank and the Little Blue Lake, which sit a short drive south of the city.
I did it as a drive-through day. Having seen what is here, an overnight would have been a better call, and I explain the accommodation options further down.
The Blue Lake is the city’s signature sight, a crater lake on the edge of town that turns a vivid cobalt blue in the warmer months, November to March, before settling back to a greyer tone for winter. The switch happens quite quickly in late spring, then deepens through the summer. I visited in January and it was the bluest water I have ever seen.
Two things to know:
You cannot swim here: The Blue Lake is Mount Gambier’s drinking water supply, so it is strictly for sightseeing. If you want to get in the water, the Little Blue Lake south of town is your swimming spot.
You can walk or drive the rim: A sealed road and walking track circle the crater for around 3.6 km, with lookouts along the way, and the Rotary Lookout makes an easy starting point with parking nearby.
The lake is also known as Warwar, its Bunganditj name, translated as the sound of many crows, and the dual name was formally adopted in 2022. The lake itself is around 75 meters deep and has supplied the city’s drinking water since pumping began in 1883. It is also one of four original crater lakes here; two of its siblings, Leg of Mutton and Browne, have since dried up as the water table fell.
There isn’t a definitive answer. But, the leading explanation is that the surface water warms in late spring, with tiny calcite crystals forming and scattering the light, flipping the lake from steel grey to cobalt.
From the Blue Lake I drove on to the Umpherston Sinkhole. A huge collapsed limestone cave has been turned into a sunken garden, with vines draping down the walls, paths and benches at the bottom, and bees working the flower beds. It is free to visit and quite magical.
Possums live around the garden, tending to appear around dusk, but if you look close enough, they can be found within the small caves in the walls. Allow half an hour or so; viewing platforms ring the top for a first look, then paths and benches take you down into the garden itself.
My satnav pulled into the wrong car park at first, if it does the same, just carry on a little further down the road and the correct one is there.
The sinkhole formed when the roof of a limestone cave collapsed, leaving a hole around 20 metres deep and 50 metres across. In 1868 a Scottish settler named James Upherston bought the land it sat on. In the 1880s, after retiring from farming, he set about turning the hole into a public pleasure garden, cutting paths and terraces into the sides and even floating a boat on a small lake at the bottom.
After his death in 1900 the garden fell into neglect, the lake vanished as groundwater levels dropped, and for a time the sinkhole was used as a rubbish tip. The restoration came in the later 20th Century, and today the sunken garden is free to visit and managed by the city.
The Blue Lake and the Umpherston Sinkhole are the main attractions, but the city has plenty more if you have a full day, or stay an extra night.
Mount Gambier’s underground world goes well beyond Umpherston, and these two are top of my list for next time:
Cave Garden, or Thugi: A smaller sinkhole right in the city centre, planned with gardens and known for its evening sound and light show. It is the easiest extra stop if you are short on time.
Engelbrecht Cave: A cave system running underneath the city streets, explored on guided tours. Tours are bookable and involve steps, so it needs a little planning rather than a drive by.
Centenary Tower: A hilltop lookout above the city with panoramic views over the crater lakes and the surrounding countryside.
Valley Lake, or Ketla Malpi: Part of the wider crater lakes precinct, with recreation areas, walking trails and local wildlife.
Riddoch Arts and Cultural Centre: The regional gallery in the city centre, a good wet weather option or a change of pace from all the geology.
With more time again, the Coonawarra wine region sits up the road and makes a natural add on for a longer stay, with day tours running from the area that combine caves, wineries and wildlife.
Mount Gambier is South Australia’s second largest city and sits directly on the country’s more recent volcanic activity. The eruptions that formed it happened only 5,000 years ago, when rising magma met groundwater in the limestone and blasted out the cluster of craters the city now wraps around.
The volcano is currently dormant rather than extinct. The volcanic field it belongs to is still considered active, but there are no signs of unrest, and any future eruptions would likely build a new vent somewhere else in the field than reopen these craters.
The Bunganditj people, on whose Country the city stands, known the mountain as Berrin. Their creation story tells of the ancestor Craitbul, whose earth ovens became the volcanoes and whose cooking fires were drowned by the rising crater lakes, which is widely understood to preserve living memory of those eruptions. I explain the story more in the Mount Schank guide.
In 1880, Lieutenant James Grant sighted the peak from HMS Lady Nelson and named it after Admiral Lord Gambier, making it the first place in what became South Australia to carry a European name. Settlement followed in the 1840s, the town was founded in 1854, and city status later in 1954.
I drove through the city, but Mount Gambier is the region’s service town and can be a great stop between Robe and the Victorian border. If I did this trip again, I would stay the night here and split the sights over an afternoon and a morning.
There are quite a few options in Mount Gambier, and most of the city’s motels cluster along Jubilee Highway or in the centre, which suits road trippers arriving late and leaving early:
Reliable motels: The Commodore is the local favourite, with updated rooms and quiet location. Mantra Mount Gambier is a good mid range option, and the Southgate Motel has a pool and restaurant a short drive from the Blue Lake.
Central and walkable: The Grand Central Motel and the Mid City Motel and Apartments sit in the town centre, within walking distance of the restaurants, the shops and the Cave Garden.
Near the Blue Lake: Blue Lake Holiday Park puts cabins, units and a pool close to the crater itself, ideal if you want the rim walk first thing in the morning or last thing in the evening.
Something different: The Old Mount Gambier Gaol, centrally located, has been converted into heritage accommodation. Delgattie Estate is a boutique pick if you want a step up from a motel.
Whichever you choose, book ahead in peak summer, especially around Australia Day and the school holidays, because the better places run out of availability quickly.
A few things I learned, one of them the hard way:
Watch the public holidays: Regional towns take public holidays seriously. I arrived on Australia Day to find the cafes closing, hence the service station sandwich. The irony I only learnt later, was that the same morning, the city’s big community Australia Day breakfast had been running at the Cave Garden. Time it better than I did, because on any normal day the city has a proper choice of cafes and restaurants.
Two hours covers the highlights: The Blue Lake viewpoints and the Umpherston sinkhole can both be done within two hours, which could be paired with a late morning at Mount Schank & the Little Blue Lake.
A full day is better: Add the rim walk, the Cave Garden, a cave tour and a Centenary Tower and Mount Gambier could easily fill a full day.
No, the Blue Lake is the city’s drinking water supply and swimming is not allowed. For a swim, head to the Little Blue Lake a short drive south of the city.
The lake turns its famous blue during the warmer months, roughly November to March, then fades to grey over winter. I saw it in January and the colour was exceptional.
Mount Gambier is dormant, not extinct, and the volcanic field it belongs to is still considered potentially active. There are no current signs of unrest, and scientists expect any future eruption would most likely form a new vent elsewhere in the field rather than reactivate these craters, so it is treated as a very low likelihood event.
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