Dolores M. Harvey/ShutterstockPrices are volatile. It doesn't matter the year, the product, or the location — for better or worse, the numbers following that dollar sign will fluctuate. What doesn't change is our needs. And as every car owner knows, fuel is a necessity.Okay, these days, maybe that "fuel" comes from the power grid, but it's still an energy source needed to propel the vehicle. For the majority of drivers, though, the fuel is gasoline, although you've got more than a few reliable diesel engines that are still going strong, too.One go-to spot for cheap food and fuel is Costco. Crazy enough, the steep gas discount can offset Costco's annual membership fee. However, Costco gas stations are also infamous for their especially long lines during peak hours, plus their offering of only regular and premium octane gasoline. But why doesn't Costco have diesel?Actually, Costco stations do sell diesel, but only at certain locations. These pumps are more plentiful than you think, but, at the same time, they are a rare sight (like the Costco car wash) when considering the number of store locations. In the U.S., there are currently 632 Costco warehouses and business centers spread across 47 states and Puerto Rico. Although not all Costcos come with a gas station on site or nearby, a large number do. And who needs those anchor stores, anyway?Costco has spun off its Kirkland Signature Fuel brand into a standalone gas station chain. As reported by the Orange County Register, the first one, a 40-pump baby Buc-cee's, opened in June 2026 in Mission Viejo, California. While this is the big-box behemoth's largest gas station to date, don't go looking for diesel. Despite its big-box dominance, only 63 Costco fuel stations offer diesel alongside gasoline.Which Costco gas stations have diesel?Cassiohabib/ShutterstockFound in 21 states, these diesel-offering Costco stations tend to be where such powertrains roam in proclivity. So, yes, they exist in California, but you won't find them in Los Angeles. These stations are more common in places like Bakersfield, Fresno, Temecula, and other cities with substantial farming communities or other industries that require heavy-duty trucks and the like.The top three states for Costco diesel also align with the top three in terms of Costco stores. California, which is home to 136 locations, leads the way with 18 diesel spots. Costco's home state of Washington follows with 11 diesel locations versus its 33 stores, and in Texas, six of its 48 Costcos offer diesel. You can look for a diesel location near you by checking Costco's list of diesel-offering fuel stations.What kind of diesel does Costco sell, and does it matter? Well, just as octane matters, there are standards regarding fuel quality as well. Like its gasoline, Costco diesel is rated as Top Tier approved. Considered high-quality fuel, many brands, from national premium-labels to regional mom-and-pops, have the Top Tier logo. To be considered, suppliers must use a proprietary package of detergent additives to be within a specific standard of performance, emissions, deposit build-ups, etc.Is Costco diesel worth it?Thearon W. Henderson/Getty ImagesDespite its limited availability, if your vehicle needs diesel fuel and you spot a telltale green-colored handle at a Costco station, top off that tank! Chances are, the price will be cheaper than a nearby diesel-serving station.Even if the pricing is comparable, Costco is a Top Tier brand, and it's rare that a Kirkland product lets us down. Also, highly-visible station attendants are on site for support and safety. For example, you're unlikely to come across a credit card skimmer with their constant monitoring. The downsides are, well, it's Costco. It's going to be busy, and long queues in the stores and at the gas stations during peak hours are the norm.The best way to avoid this time suck, especially at the pumps, is to pop in when the warehouse itself is still closed. Costco store hours are similar across the country. They're generally open from 10:00 a.m. to 8:30 p.m. on weekdays. If you're a high-roller Executive Member, you may be able to start shopping at 9:00 a.m.Although not 24-hour operations, the gas stations are accessible outside of store hours. The standalone station in Southern California, for example, operates from 5:30 a.m. to 10:00 p.m., which is typical for Costco. But some stations, like one in Honolulu, are open as early as 4:30 a.m. So, definitely check the location details before heading over.Also, don't forget your Costco card. The TSA won't accept your Costco card as a form of identification, but the Costco fuel pumps require it. Have a Visa credit card handy, too, because even though you can use cash for a hot dog-and-soda combo at the food court, you'll need plastic at the pumps, regardless of what fuel you're filling up with.Want more like this? Join the Jalopnik newsletter to get the latest auto news sent straight to your inbox, and follow us or add us as a preferred search source on Google.
