Mount Gambier
The Blue Lake and the Sinkhole City
On the lands of the Boandik people.
schedule 1 min read / Updated Jun 2026
The largest city in regional South Australia, built around the dormant Mount Gambier volcano. The city is famous for the Blue Lake, a crater lake that turns vivid cobalt blue every November and stays that way until April.
Mount Gambier sits on the slopes of an extinct volcano with at least four crater lakes within the city limits. The volcano last erupted around 5,000 years ago, making it one of the youngest volcanoes in mainland Australia.
The Blue Lake is the most famous of the crater lakes. Every November the water turns from a dull steel grey to an intense cobalt blue, a transformation that scientists still don't fully understand but believe is caused by changes in surface water temperature, calcium carbonate, and iron content during the warmer months. The colour fades back to grey in April. The lake is the city's main water supply.
The Umpherston Sinkhole, in the centre of town, is a collapsed limestone cave that has been turned into a sunken garden with terraced flowers and hanging vines. Possums emerge at dusk and are happy to be hand-fed by visitors.
The wider Limestone Coast is famous for sinkholes, caves, and the world-class Coonawarra wine region 50 kilometres north.
Tourist locations
Places to visit in Mount Gambier.
9 locations to explore
Blue Lake
The Volcanic Crater Lake That Changes Colour
Full guide arrow_forwardCave Garden / Thugi
City sinkhole, ancient heart
Free
Full guide arrow_forwardEngelbrecht Cave
Underground lakes beneath the city
$14.50 adult, $8.50 child (4-17), $40 family
Full guide arrow_forwardEwens Ponds Conservation Park
Three crystal ponds, one float
Park entry free; snorkelling permit approx $17.50 adult
Full guide arrow_forwardMount Schank State Heritage Area
Walk the rim of a volcano
Free
Full guide arrow_forwardNaracoorte Caves National Park
World Heritage fossils in living caves
Park entry free; tours from $13 adult (self-guided) to $39 adult (guided Victoria Fossil Cave)
Full guide arrow_forwardTantanoola Caves Conservation Park
Pink dolomite show cave
$17 adult, $9.50 child (4-15), $44.50 family
Full guide arrow_forward
Umpherston Sinkhole
The Sunken Garden in a Collapsed Limestone Cave
Full guide arrow_forwardWynns Coonawarra Estate
Terra rossa Cabernet icon
Free (tastings complimentary or by glass purchase)
Full guide arrow_forwardScenic views
Lookouts near Mount Gambier.
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Attribution
Sources & credits
Content (1)
Images (2)
- Mount Gambier Airport 2021.jpg · Conorjdunne · CC BY-SA 4.0
- Mount Gambier Airport Interior 1.jpg · Conorjdunne · CC BY-SA 4.0
Images sourced from Wikimedia Commons under licenses that permit commercial use. If you are the rights holder and believe an attribution is incorrect, please contact us.