Tasmania Diesel Lifts 13.2 Cents in a Day as the Island State Overtakes the Mainland
The number that caught my eye this morning is 13.2. As of 16th Aug 2026 8:06am AEST, the diesel average in Tasmania has lifted 13.2 cents to 251.1, the largest single day diesel move of any Australian state and a 5.6 per cent rise in 24 hours. That is enough to make the island the most expensive state in the country for diesel.
Tasmania rarely tops these tables. The state's 49 diesel reporting stations usually sit quietly in the middle of the pack, so a morning where they lead the country stands out.
A reset across the whole island
Yesterday Tasmanian diesel averaged 237.9. This morning it is 251.1, with pumps running from 231.9 at the cheapest to 269.5 at the dearest. A state average does not move that far in a day on the back of one or two outliers. A shift this broad looks like a coordinated round of price resets rolling through most of the island's sites on the same morning.
For context, here is how every state's diesel average moved over the same 24 hours:
- Victoria: 245.5, down 1.3 cents and the only state to ease
- New South Wales: 247.1, up 0.2 cents
- Queensland: 248.3, up 3.9 cents
- South Australia: 249.8, up 5.0 cents
- Western Australia: 250.4, up 2.8 cents
- Tasmania: 251.1, up 13.2 cents
Until this morning, Western Australia and South Australia held the top two spots. Tasmania has moved past both in a single session.
The tightest spread on the board
The spread interests me more than the average does. The gap between Tasmania's cheapest and dearest diesel pump is just 37.6 cents, the narrowest of any state. Western Australia's spread is 167.1 cents, New South Wales sits at 134.2, South Australia at 121.5, Queensland at 111.4 and Victoria at 103.4.
A tight spread cuts both ways. It means fewer pricing traps for motorists who fill up without checking, but it also means fewer standout bargains. On the mainland, the cheapest suburbs sit well under their state averages. Rocklea in Brisbane's south is averaging 235.4 with a low of 225.5, Archerfield has diesel from 226.5, and in Melbourne both Preston and Thomastown have pumps in the 226 to 229 range. Tasmania's single cheapest pump, at 231.9, sits above every one of those mainland lows.
What the numbers mean for your next fill
Even on an island where prices move together, a quick check before filling still pays. Statistically speaking, a 37.6 cent spread on a 60 litre tank is a difference of more than $22 between the cheapest and dearest fill in the state.
Three things follow from the data.
- Shop the bottom of the range. Pumps at 231.9 are still out there, nearly 20 cents under the new state average, and checking live diesel prices before you drive takes seconds.
- Do not assume the move is over. Resets of this size are often followed by smaller adjustments in the days after, and the price trends page is the easiest way to watch whether 251.1 settles in as the new normal or turns out to be a short lived peak.
- Petrol drivers can relax for now. This morning's movement was concentrated in diesel, and unleaded moved far more modestly around the country, though Hobart motorists should keep an eye on whether petrol follows diesel's lead this week.
The bigger picture
Diesel has been drifting upward across most of the country for a fortnight, and Tasmania's move fits that pattern, just compressed into a single day. Victoria easing while five states lifted is the counterpoint here, and the one worth watching over the coming week.
The numbers are clear: Tasmania's diesel market reset firmly overnight, but motorists who compare before they fill can still claw back most of the increase. On current data, that 37.6 cent spread is the difference between wearing the rise and largely sidestepping it.
