Tasmania Holds the Steadiest Diesel in the Country While the Mainland Spread Tells Another Story
The most interesting number in this morning's data is not a price. It is a gap. As of 8:05am AEST on 20th Jun 2026, Tasmania is running a diesel average of 206.9 cents per litre, one of the dearest in the country, yet the distance between its cheapest and dearest servo is just 33 cents. On the mainland, that same gap stretches past 130 cents in several states. Where you fill up matters far more in some places than others, and the data shows exactly where.
Tasmania pays more but worries less
Tasmanians are not getting a bargain here. At 206.9 cents, the island's diesel average is the second highest in the country, behind only the Northern Territory at 230.3 cents. The cheapest diesel tracked across the state sits near 193.9 cents, with the dearest reaching 227.3.
The consistency is the part that caught my eye. Across 43 reporting stations, the entire Tasmanian diesel market fits inside a 33 cent band. Whether a motorist fills up in Hobart, Launceston, Devonport or Burnie, the price is broadly the same. For a state usually defined by distance and freight costs, that uniformity is unusual.
It also changes the advice. In Tasmania, driving across town to chase a cheaper pump rarely pays. The saving is measured in a few cents, not the double digit gaps you see elsewhere.
The mainland is a different game entirely
Compare that with the bigger states. The Northern Territory shows a spread of more than 150 cents between its cheapest and dearest diesel, the widest in the country. Western Australia and New South Wales both sit around 135 cents. That means two servos in the same state, sometimes only a short drive apart, can differ by well over a dollar a litre.
This is where checking before you fill genuinely pays. In a market that wide, the motorist who compares prices can save real money. A 130 cent gap on a 70 litre tank is not loose change. It is the better part of a hundred dollars left on the table for anyone who fills up on autopilot.
Victoria has the most encouraging headline for value, with the lowest state diesel average at 191.2 cents. Even there the spread runs past 100 cents, so the cheapest Victorian diesel and the dearest are a world apart.
Why the spread varies so much
A couple of things sit behind the pattern. Larger states carry remote and regional pumps where freight and thin competition push prices high, dragging the maximum upward and stretching the spread. Tasmania is compact, and its stations cluster within a smaller geographic and competitive range, so there are fewer extreme outliers and the band stays tight.
It is the same reason the Australian Capital Territory posts the narrowest spread of all, around 12 cents. A small, urban market with no remote highway servos simply has less room for prices to drift apart.
What it means for your tank
The value of comparing prices depends heavily on where you live. For Tasmanian motorists, filling up close to home is perfectly sensible, since hunting around claws back very little. The smarter move there is timing the fill rather than the location, and our best time to fill up guide breaks down how the cycles move.
For drivers in the larger mainland states, the opposite holds. With spreads above 130 cents, a quick check before you pull in can be the difference between a fair price and a poor one. Watching the diesel prices in your area is the easiest way to steer clear of the dearest pumps.
Statistically speaking, the motorists who gain most from comparison shopping are not in the calm markets like Tasmania. They are in the sprawling, wide spread states where the same fuel can cost a dollar more just down the road. The numbers are clear: knowing your local spread is worth as much as knowing the average.
