Fascinating Mount Gambier Sinkholes To Visit

Fancy a swim in a dazzling cobalt waterway, or a stroll around a lush, emerald wonderland? The famous Mount Gambier sinkholes can set the mood for every kind of adventure.

Reykjavik, Naples, Cartago; when you’re yearning to explore a dramatic volcanic landscape, there’s only one destination where the sinkholes – a depression caused by the collapse of the surface layer – are a celebration (particularly in the warmer months): Mount Gambier on South Australia’s spectacular Limestone Coast.

Proving that good things are worth the wait, geologists believe that Mount Gambier’s (justifiably) famous sinkholes are the result of rain on the region’s three fault lines breaking up the huge expanse of limestone, more than 25 million years old, spanning South Australia’s south-east. Water flowing through the limestone has formed 50 sinkholes, with at least 15 of them filled with water.

So, when is the best time to take advantage of Mount Gambier’s sinkholes? While Mount Gambier itself is a treat to visit year-round, aqua babies are best to plan a trip in the warmer months, between November and March, when the water is less biting and the colour morphs from a hue which can fall anywhere from steel grey or garden variety blue to vibrant cobalt. The good news? Whether you hire a car and drive to each spot (easily done since most of the major holes are located within a 20-minute drive of one another) or book a tour, there’s the perfect sinkhole experience for every kind of traveller, including these tourism-heavy hitters.

Kilsby Sinkhole

Will it be snorkelling, scuba diving, free diving or a sinkhole tour of the training site for the South Australian Police? At Kilsby Sinkhole , located on a sheep farm among the rolling grasslands of Moorak just 14 kilometres south of Mount Gambier, you can choose all of the above.

Out here, where it’s not unusual for people to show up in mermaid outfits for the ultimate photoshoot, water clarity has drawn people to the site for decades, the giant chasm descending 65 metres and allowing up to 50 metres (most days) visibility for scuba drivers and freedivers, and pristine water clarity for those who prefer to frolic towards the surface. 50-minute guided tours cover the sinkhole’s fascinating history and geology – a real hit with the kids.

a diver facing the light as it passes through the water under Kilsby Sinkhole — It’s a stunning sight when the sun rises over Kilsby Sinkhole. (Image: Adam Stern)

Snorkelling tours run for two hours, complete with a safety briefing and under the supervision of a snorkel supervisor, while those interested in diving and freediving can book a licensed operator to help their dream come true.

Kilsby Sinkhole is a privately owned site, thus, all visits must be pre-booked online. The good news? They now offer a range of two-bedroom luxury villas at a surprisingly affordable price point, so you can take advantage of the sinkhole (and its surrounds) day after day.

Umpherston Sinkhole

In the middle of Mount Gambier’s city streets, a lush, subterranean oasis blooms some 20 metres deep in a natural well providing cool respite for those who want to escape those blazing days, but don’t much fancy getting wet.

Named after its designer James Umpherston who designed this urban botanic garden in the late 1800s, Umpherston Sinkhole/Balumbul (one of the most photographed locations on the Limestone Coast) was once a cave formed through the dissolution of the limestone, becoming a sinkhole only after the top of its chamber collapsed and its topsoil provided the perfect environment on which flora to grow.

lush greenery at Umpherston Sinkhole — Stroll through the enchanting vines. (Image: South Australian Tourism Commission/Adam Bruzzone)

Now it’s best described as a gateway to a secret world filled with hanging vines and terraces, the depth and scale of which is best enjoyed from the viewing platforms before taking a walk down to the bottom to view the hydrangeas (but only after grabbing an ice cream or coffee from the onsite kiosk). Yep, at Umpherston Sinkhole, it’s all about walking and observing.

Beautiful any time of day, locals swear by a visit at dusk when the friendly locals, the Umpherston possums, come out to greet their visitors. Why not stick around and make use of the free barbecue area?

Little Blue Lake

Disregard its name; Little Blue Lake is actually a sinkhole with a difference: the ability to change colour like a mood ring so that the steel grey it rocks throughout the winter months transforms into a vibrant cobalt blue come the summertime (November to March). It’s all thanks to a phenomenon caused by the formation of calcite crystals warmed by the rays of the sun.

Located in the Kanawinka volcanic area, wedged between the two (mercifully) dormant volcanoes of Mount Gambier and Mount Schank, follow the campervans making a line to Little Blue Lake, which is conveniently situated in a paddock by the highway.

a diving platform above the milky turquoise waters of Little Blue Lake, Mount Gambier — Mount Gambier’s Blue Lake transforms into milky turquoise between November and March. (Image: Lucy Adamopoulos)

With a 47-metre depth, plus a diameter of 40 metres, the lake is what you might call bracing – a fact locals love and visitors quickly get used to as they enter the sinkhole via the stairs or ramp. Your best bet? Warm up beforehand or afterwards by lying out in the sun, or by enjoying a picnic (you’ll have to bring your own provisions). Just beware that there are no public amenities, so best to use the bathroom before you depart from your accommodation.

Got plenty of time in and around Mount Gambier up your sleeve and are keen to experience further sinkholes? Be sure to also put Ewens Ponds, Hell’s Hole and Caroline Sinkhole on your list.

Wanting to explore the rest of Mount Gambier? Follow our guide for awe-inspiring things to do in Mount Gambier.

We round up the luxe, the lovely and the latest places to stay in regional Victoria.

1. Hotel Ernest, Bendigo

Settle into this artful lodging in the city centre for a boutique stay with heritage roots dating back to 1864. Each of the 10 suites in this former bank is elegantly styled and furnished with covetable works by Australian artists. Ernest is also home to the much-lauded Euro-style Restaurant Terrae, so be sure to book into the two-level diner during your visit.

2. Norsu Cabin, Macedon

a look inside Norsu Cabin, Macedon — Settle into this Scandi-inspired abode. (Image: Nick Skinner)

Country cabin dreams come to life under the sweet timber A-frame of Norsu . Sleeping eight guests, this Scandi-inspired abode is so meticulously styled it’s received knowing nods from The Design Files and is everything a modern log cabin should be, including cosy fireplace, fire pit, modern appliances and French linens. Perfect for logging out of daily life for a moment.

3. Islay House, Woodend

the bedroom at Islay House, Woodend — Bed down at the gorgeously restored heritage Islay House. (Image: Tiffany Warner)

Lean all the way into a country luxe state-of-mind with a stay at the gorgeously restored heritage Islay House . This bed and breakfast sleeps up to nine guests and is just a short walk from town, but you’ll want to spend most of your time curled up fireside in the elegantly styled rooms as you admire the collection of antiques.

4. Nerissa Rye, Mornington Peninsula

This Rye beach pad is just a 10-minute walk from 16th Beach, and while a morning walk is lovely, returning to the barefoot luxe vibes of this four-bedroom escape is just as enlivening. Bright, open and welcoming, this is the place to settle in for endless cups of tea and a good book between beach jaunts.

5. Hotel Vera, Ballarat

a close-up of the bed at Hotel Vera, Ballarat — Modern meets bygone elegance.

This Ballarat beauty set in a 1900s mansion is all bygone elegance edged with modern style. Just seven boutique suites, each with its own distinct personality, makes it a singularly luxe stay. Sister to Bendigo’s Hotel Ernest, Vera is similarly bequeathed with a stand-out fine diner, Babae, which plates up the best of the region’s produce.

6. Hotel Sorrento, Port Philip Bay

The historic and iconic clifftop Hotel Sorrento at Port Philip Bay is mid-refurb and will reopen 1 December 2025, just in time for Amalfi-style beachside stays.

7. The Idle Lake House, Lakes Entrance

Enjoy a ripple of serenity when you step aboard this water-top abode on the Gippsland Lakes. Once a Chinese restaurant, this spacious and stylish two-bedroom stay offers unbroken gazing of the shimmering surface in a beautifully private bay. Lounge on the deck and enjoy the onboard bathhouse; come evening, sit by the sleek suspended fireplace.

8. The Monty, Anglesea

the bedroom at The Monty, Anglesea — Bed down at the vintage motel, The Monty.

Palm Springs makes an entrance on the Great Ocean Road with the opening of The Monty in October 2025. Its vintage motel meets modern muse at this playful boutique stay complete with pool and a vibrant Mexican cantina. You’re just a stroll from the beach here, which tells us it’s ripe for summer vacays this season.

9. Trentham Waters Resort, Mildura

vibrant bedroom wall and pillows at Trentham Waters Resort, Mildura — The bright and retro-style bedroom at Trentham Waters Resort.

Another new property lands in regional Victoria in time for an endless summer with Trentham Waters Resort expected to open by February 2026. Breezy, subtly retro and brightened by the big Mallee sky, this river’s-edge escape is perfect for settling in for a spell with one-, two- and three-bedroom villas. There’s a lagoon-style pool, riverside hot tubs and onsite dining for all your relaxation requirements.

10. Crowne Plaza, Geelong

the Trattoria Bar in Crowne Plaza, Geelong — Sink a cold one at the Trattoria Bar.

Geelong is getting its own Crowne Plaza in 2026. Its arrival on the waterfront will make it the city’s largest (and newest) hotel with 200 contemporary rooms and suites, a Skybar, all-day dining, indoor pool and gym, and event spaces. Keep it on your radar.

11. Re’em, Yarra Valley

a private tub with lush views at Re’em, Yarra Valley — Sip and soak in tranquillity.

With verdant Yarra Valley views that take in the linear beauty of tended grapevines, the 16 suites and rooms at Re’em are set amid the Helen & Joey Estate and invite sipping and sitting in tranquillity. The onsite restaurant deftly balances Chinese and Australian flavours and if you’re staying over the weekend, be tempted out of your stylish room for yum cha that features delicate handmade dumplings and vineyard vistas.

12. Arapiles Clubhouse and Crash Pad, Grampians

the yard front door of Arapiles Clubhouse and Crash Pad, Grampians — Spend an overnight stay in the Natimuk stone house. (Image: Bianca Jackson)

These 1880-era mountain-adjacent digs have been tenderly restored to provide rock climbers and Grampians country wanderers a chic place to rest. You’ll find four bedrooms in the Natimuk stone house, as well as a heated pool out the back and plenty of luxe embellishments. There’s also a two-person ‘Crash Pad’ in the confines of the Clubhouse with its own separate entrance.

the lounge at Arapiles Clubhouse and Crash Pad, Grampians — The Crash Pad offers a resting place for rock climbers and Grampians country wanderers. (Image: Bianca Jackson)

The fascinating sinkholes in Mount Gambier to visit