Cheapest U91 Fuel Prices around Underdale, SA Today

The cheapest U91 around Underdale, SA is 159.50 cents per litre at Liberty Beverley, 780 Port Road.

Based on the past 4 weeks, Mondays tend to have the cheapest U91 prices around Underdale, averaging 154.80 c/L. Fridays tend to be the most expensive at 157.20 c/L – a difference of 2.4 cents.

FuelTrack tracks prices at 42 stations selling U91 around Underdale, SA. The area has 7 fuel types available, including LPG, E10, U91, U95.

There are 6 fuel brands around Underdale including Liberty, U-Go, United, Mobil, Independent, Ampol. Compare prices across all brands to find the cheapest fuel.

Fuel excise is the federal tax built into the price of every litre of petrol and diesel. It normally rises twice a year in line with inflation, and in early 2026 it sat at 52.6 cents a litre. When conflict in the Middle East pushed oil prices higher, the government brought in cost-of-living relief: from 1 April it roughly halved the excise, taking about 32 cents a litre off the bowser price. On 20 June that relief was extended into July but tapered to a 16 cent cut, lifting the excise to 36.6 cents, so pump prices rose at the start of July. The reduced rate runs until 2 August. From 3 August the full 52.6 cent excise returns, and because GST is charged on top of it, that's expected to add about 18 cents a litre at the pump, or roughly $9 on a 50-litre tank, unless retailers absorb part of the increase. A routine inflation adjustment in early August nudges the rate a little higher again.