Mount Gambier Premium Petrol Drops 13 Cents as Riverland Servos Hold Diesel Under 239
Right, so while everyone's been carrying on about the Gold Coast and Perth lately, the numbers that jumped out at me this morning are all from South Australia. As of 8am on Wednesday 26th Aug 2026, there are two stories out of SA worth your time. Premium petrol in Mount Gambier has come back a solid 13 cents, and out in the Riverland they're pouring some of the cheapest diesel in the state.
Mount Gambier premium finally gives a bit back
Down south, six servos around Mount Gambier are now averaging 221.8 a litre for premium 98, down 13.1 cents from 234.9. That's a proper move, not a token gesture. On a 50 litre tank you're keeping about six and a half bucks in your pocket, which is a schooner and change at the local.
Now, if you read my piece on Corio a few weeks back, you'll know what I reckon about premium drops like this one. Premium buyers are a small crowd, so when servos start trimming premium 98 prices, it usually means they're sharpening the pencil right across the board. If you're a regular unleaded driver around Mount Gambier, keep an eye on things over the next few days, because the cheaper end of the cycle tends not to be far behind.
The Riverland is the diesel bargain nobody's talking about
Here's the thing, right. The statewide average for diesel in SA this morning is sitting at 257.1. But head up to the Riverland and it's a different story altogether.
In Barmera, the cheapest servo has diesel at 238.5, and the three servos in town average 241.3 with only 8.4 cents between the cheapest and the dearest. Down the road in Berri, the cheapest is also 238.5, though the town average is 244.1 because the dearest servo wants 253.9. That's a 15.4 cent gap inside one town, so picking the right driveway in Berri saves you about nine bucks on a 60 litre fill. Fair dinkum, same fuel, same postcode.
Put it against the state average and the Riverland looks even better. At 238.5 you're paying nearly 19 cents a litre less than the SA average. Fill a 60 litre ute tank and that's about eleven bucks staying in your wallet, every single time. Do that once a week and you've shouted yourself a decent slab by the end of the month.
If you're hauling up the Sturt Highway with a van or a boat on the back, plan the fill around Barmera or Berri rather than topping up wherever the gauge gets nervous. Have a squiz at live diesel prices before you leave and lock the plan in.
How SA stacks up against the rest
For the bigger picture, Victoria is the cheapest mainland state for diesel this morning at 253.2 on average, with NSW at 254.1 and Queensland at 255.3. Western Australia sits at 256.3 and SA at 257.1, so we're at the dear end of the mainland pack. Spare a thought for the Northern Territory though, where the average is knocking on 292. Makes 238.5 in Barmera look like an absolute gift.
The other thing the numbers show is how much spread there is inside SA itself. The cheapest diesel in the state this morning is 234.9 and the dearest is 350. That's a difference of more than a dollar a litre depending on where you pull in. Nobody's driving across the state to save on fuel, obviously, but it does prove the point I bang on about every week: the servo you choose matters more than the day you fill up, most of the time.
What I'd do about it
If you're in Mount Gambier and you run premium, this is your window, and if you run unleaded, the next few days are worth watching on price trends. If you're anywhere near the Riverland with a diesel, Barmera at 238.5 is the pick of the state, and in Berri make sure you're at the cheap servo and not the dear one, because 15 cents is 15 cents.
Look, end of the day, a bit of planning means more cash in your pocket for the important stuff. Can't argue with that.
