Diesel matters far more to Costco shoppers in the UK than in the US. Here every Costco petrol station sells it, and the pump is labelled "Premium Diesel". This post covers which UK Costcos have diesel, what it costs against the UK average, what "premium" means on a Costco pump, how it compares with Shell V-Power Diesel and BP Ultimate Diesel, and where to get AdBlue.
Short answer: All 22 UK Costco petrol stations sell diesel, and it is the only diesel they sell: Kirkland Signature Premium Diesel. On 12 October 2026 it averaged 191.08p per litre, 9p below the UK average of 200.04p that day, and by our 15 October reading it was 190.4p. Costco says it meets BS EN 590 with a minimum cetane number of 51, the same minimum as any UK diesel. The "premium" part is Costco's additive package, not a higher cetane rating. For today's price at each station, see Costco diesel price today.
Which UK Costcos sell diesel?
All of them that have a petrol station. Costco has 29 UK warehouses in our data, and 22 have a forecourt. Every one of those 22 posted a diesel price on 15 October 2026. Costco's Kirkland Signature Fuel page lists three grades for its UK forecourts: Unleaded, Premium Unleaded 97 and Premium Diesel. Our warehouse data shows three fuel codes at every UK forecourt, which matches those three grades.
| Region | Costco petrol stations with diesel |
|---|---|
| Scotland | Aberdeen, Edinburgh, Glasgow |
| North of England | Gateshead, Leeds, Sheffield, Manchester, Oldham, Haydock, Liverpool, Chester |
| Midlands | Birmingham, Coventry, Derby, Leicester |
| South of England | Bristol, Reading, Southampton, Sunbury, Watford, Stevenage, Thurrock (Lakeside) |
Seven warehouses have no petrol station at all: Cardiff, Chingford, Croydon, Farnborough, Hayes, Milton Keynes and Wembley. If one of those is your local Costco, the near-me finder shows the closest forecourt that does sell fuel. The full list, with addresses and hours, is on Costco petrol stations in the UK.
Diesel pumps keep the same hours as the rest of the forecourt, which are not the same as the warehouse. See Costco petrol opening times, and why the forecourt opens before the warehouse.
How much is diesel at Costco today?
Prices change most days, so the live figures are on Costco diesel price today, with every station ranked, a postcode finder and 30 days of history. Here is the snapshot from our 15 October 2026 reading, across all 22 stations:
| Costco diesel, 15 October 2026 | Price |
|---|---|
| Average across 22 stations | 190.4p/L |
| Cheapest | 184.9p/L (Edinburgh and Watford) |
| Most expensive | 194.9p/L (Reading and Southampton) |
| Average a month earlier (16 September) | 182.9p/L |
| Median gap over unleaded, same station | 25p/L |
| Median gap over Premium Unleaded 97, same station | 14p/L |
So filling a 55-litre tank at the average Costco price cost about £104.72 that day. The 10p spread between the cheapest and dearest Costco is worth about £5.50 a tank, so it can pay to check before you drive.
Costco diesel rose about 7.5p a litre in the month to 15 October. That follows the wider market. The RAC reported on 2 October 2026 that the UK average diesel price had reached a record 200.01p a litre, passing the previous record of 199.09p from June 2022.
Is Costco diesel cheaper than the UK average?
Yes, by about 9p a litre right now. The government's weekly road fuel prices put the UK average for diesel at 200.04p a litre on Monday 12 October 2026. Costco's average that day was 191.08p, 9.0p lower, and by 15 October it was 190.4p.
| Costco average (our data) | UK average (gov.uk weekly) | Costco cheaper by | |
|---|---|---|---|
| Diesel, mid-October 2026 | 191.08p (12 Oct) | 200.04p (12 Oct) | 9.0p |
| Diesel, mid-September 2026 | 182.9p (16 Sep) | 190.72p (w/c 14 Sep) | 7.8p |
| Unleaded, mid-October 2026 | 166.58p (12 Oct) | 175.28p (12 Oct) | 8.7p |
The October figures are from the same day. The September ones are two days apart, so read that gap as approximate. On a 55-litre fill, 9p a litre is about £4.95. Membership is the catch: you need a Costco card to use the pumps (which memberships work), so the saving only adds up if you would be a member anyway or you fill up often. Our is Costco fuel cheaper post works out how many litres pay back the fee, and compares Costco with Tesco, Sainsbury's, Morrisons and Asda.
Is Costco premium diesel actually premium?
Partly. It is premium in the additives, not in the cetane rating.
Cetane number measures how quickly diesel ignites once injected. Higher cetane means a shorter delay, which can help cold starts and smoothness. The UK diesel standard, EN 590, sets a minimum cetane number of 51 for all road diesel, a maximum of 7% biodiesel (FAME, hence the "B7" label on the pump) and a maximum of 10 mg/kg of sulphur.
Costco does not quote a cetane number on its current Kirkland Signature Fuel page. The figure UK drivers quote comes from Costco's own past answer to a customer, repeated on the MBClub forum in March 2022:
"In accordance with BS EN 590, our Premium Diesel has a minimum cetane number of 51. All of our fuels are additised on site using bespoke additive packages."
A minimum of 51 is exactly what EN 590 requires of any diesel. So Costco is not promising a higher cetane number than a supermarket's standard diesel. What Costco does claim, on its fuel page, is that "every grade of Kirkland Signature Fuel contains additives" that clean injector deposits and prevent new ones, which it says helps restore fuel economy and performance and reduce emissions. Costco has not published lab results for UK diesel, so we cannot verify those claims independently.
Owners on UK forums reach the same view. A March 2025 thread on MoneySavingExpert titled "How Premium is Costco Premium Diesel?" notes that Costco claims a minimum cetane of 51 against 56 claimed for Shell V-Power Diesel.
Costco premium diesel vs Shell V-Power Diesel and BP Ultimate Diesel
The big brands' premium diesels are sold alongside their standard diesel, at a higher price. Costco sells only one diesel, so its Premium Diesel is priced against everyone else's standard diesel.
| Costco Premium Diesel | Shell V-Power Diesel | BP Ultimate Diesel | |
|---|---|---|---|
| Meets EN 590 | Yes | Yes | Yes |
| Cetane | Minimum 51, per Costco (2022 statement) | Commonly quoted as 55 or 56 on forums; no current official UK figure found | Commonly quoted as 55 on forums; no current official UK figure found |
| What the brand claims | Cleaning additives in every grade, blended on site | Cleans up to 100% of performance-robbing deposits | Cleaning additives ("ACTIVE technology") |
| Sold alongside a cheaper diesel? | No, it is the only diesel | Yes | Yes |
Shell's deposit claim is reported by Forecourt Trader from its 2023 relaunch. We could not find a guaranteed cetane number on Shell's or BP's current UK pages; the 55–56 figures for V-Power Diesel and 55 for BP Ultimate Diesel come from a comparison table posted on the MBClub forum in 2019, so treat them as unverified.
In plain terms: if you want the highest cetane fuel you can buy, Shell V-Power Diesel or BP Ultimate Diesel are the likelier bet, though their figures are unverified, and at a higher price. If you want a detergent-treated diesel for less than most supermarkets charge for standard diesel, Costco's is that.
Is Costco diesel any good for my car?
Yes, for any diesel car or van built for UK pump fuel. It meets the same EN 590 standard as every other UK forecourt, with up to 7% biodiesel like any B7 diesel. If your handbook calls for EN 590 or B7 diesel, Costco's qualifies.
Two practical points:
- Cetane-sensitive engines. Some owners of high-performance or older diesels notice a difference with higher cetane fuel. If that is you, fill with V-Power or Ultimate now and then, or before a long trip. Nothing in EN 590 says you have to.
- Winter diesel. EN 590 sets cold-weather grades by temperature class, so winter diesel in the UK is a seasonal grade of the same standard. Costco does not say anything different about its winter supply.
Forum reports are mostly positive, but they are anecdotes, not tests. Our Costco fuel quality post covers the UK standards and Costco's additive claims for all three grades. For the wider "is Costco fuel bad for your car" myths, see our myths post, which is written about the US but covers the same questions about cheap fuel.
Does Costco sell AdBlue in the UK?
Yes, in bottles, not at the pump. Costco UK lists Redex AdBlue in a 10-litre bottle with spout (item 439500), described as ISO 22241 compliant. We could not load the price or stock status, and warehouse stock varies, so check the Costco app for your warehouse before going.
We found no UK Costco forecourt with an AdBlue dispenser. Third-party fuel listings describe Costco's forecourt AdBlue as "packaged", which fits. If you need AdBlue from a pump, some truck-friendly forecourts have one; BP announced AdBlue pumps at 40 UK sites back in 2018.
How to check today's Costco diesel price
- Our diesel page. Costco diesel price today ranks all 22 stations by today's diesel price, with a postcode finder and 30 days of history.
- Station pages. Each station page, for example Costco Birmingham, shows today's unleaded, Premium Unleaded 97 and diesel prices with history. Start from the UK hub.
- Costco. Costco's website and app show prices for each warehouse's petrol station.
Remember you need a Costco membership card to pump. Costco's £120 pre-authorisation buys about 63 litres of diesel at today's average, so a big tank filled from empty can hit the limit; see how to pay at Costco petrol. If you are coming from the US, note the differences: UK Costco diesel is priced in pence per litre, every UK forecourt sells it, and there is no Top Tier scheme here. Our US post on which Costcos sell diesel covers the American picture.