Bottom line up front: Kirkland Signature diapers are still the best cost-per-change in mainstream retail, and they are no longer the diaper they were two years ago. Costco switched manufacturers in January 2025 — from Kimberly-Clark, the company behind Huggies, to First Quality, the company behind Cuties — and the current diaper is thinner. For daytime changes that is mostly fine. For a heavy overnight wetter it is the difference between a dry morning and a sheet change.
I have bought Kirkland with my own money across both eras, and affiliate links never change my verdicts. Here is the honest version.
What changed in 2025
This is the part almost no review mentions, and it is the single most important fact about this diaper.
Until the end of 2024, Kirkland Signature diapers were made by Kimberly-Clark. That is why the “Kirkland is just Huggies in a different bag” theory was so persistent, and why the comparison held up so well in practice. Bloomberg reported the supplier change, and by spring 2025 Fortune was covering the parent backlash: the new diaper, made by First Quality, was described as paper-thin, with complaints about leaking and a boxier, less forgiving shape, and hundreds of one-star reviews on Costco’s own site.
Costco’s response, per that reporting, was that the thinner build is deliberate and reflects an industry-wide move toward slimmer diapers, that it found no manufacturing fault, and that it does not intend to change suppliers again. Diaper Dabbler, a diaper-sampling retailer that tracks these changes closely, describes the current diaper as thin and trim in the same family as Luvs — which matches what mine felt like out of the box.
Two things follow. First, any Kirkland review written before 2025 is describing a different product. Second, my own Kirkland vs Huggies comparison rests on a manufacturing overlap that no longer exists, and I would now read that post as a value argument rather than a same-factory argument.
The spec sheet, decoded
Costco publishes a short feature list, and it is more informative than most:
| Claim on the box | What it means in use |
|---|---|
| Super absorbent core, up to 12 hours | A marketing ceiling, not a promise. True for a light wetter, optimistic for a heavy one |
| Hypoallergenic liner | No fragrance, parabens, phthalates, lotions, elemental chlorine or natural rubber latex |
| Pocketed waistband | The blowout feature that matters most in the first six months |
| Wetness indicator | A stripe that turns blue — genuinely useful in the newborn fog, irrelevant by month four |
| Next size indicator | A printed cue that you have outgrown the box, which you already knew |
| Stay-put strips | Refastenable tabs that survive a mid-change check |
Sizes start at 1. There is no newborn size, which matters if you are buying ahead for a baby who might arrive small — you will need a different brand for the first weeks either way.
The ingredient exclusions are real and worth the credit. If your reason for shopping the ingredient list is fragrance or lotion sensitivity, Kirkland qualifies on paper as well as the premium brands do, which is not something you can say about every warehouse label. My Coterie review covers what actually changes when you pay four times as much.
How the current diaper performed
Daytime: fine, and that is most of the job. Two or three hours between changes, a normal amount of squirming, no leaks worth reporting. If you are getting through eight to ten changes a day, this diaper handles the overwhelming majority of them without ever entering your thoughts. That is what a good commodity diaper is supposed to do.
Blowouts: better than the price suggests. The pocketed back waistband does the thing it claims to do. Compared with genuinely cheap store brands, this is where Kirkland still separates itself.
Overnight: this is where it gave up. The thinner core is not a rumor you can talk yourself out of at 3 a.m. Eleven or twelve hours on a heavy wetter is beyond it, and the failure mode is a wet pyjama leg rather than a dramatic blowout. My workaround is unglamorous and cheap: Kirkland all day, a purpose-built overnight diaper at bedtime. A box of Pampers Swaddlers Overnights lasts a surprisingly long time when it is only doing one change a day.
Fit: boxier than it used to be. On a lean, long baby the current cut runs straighter through the leg, and the tabs need a deliberate pull to sit right. On a chunkier baby I noticed nothing.
Rash: no change I could attribute to the diaper. Rash is usually about change frequency and moisture, not brand — if you are chasing one that will not clear, Betteroo’s explainer on telling a plain diaper rash from a yeast rash is a better use of an evening than a brand switch.
Cost per change: still the winner
Kirkland’s whole argument is arithmetic, and the arithmetic survived the supplier change intact.
Depending on size and box count, Kirkland lands roughly in the mid-teens to low-twenty cents per diaper at the warehouse. Mainstream name brands typically run somewhere from the mid-twenties to the mid-thirties. On roughly 2,500 diapers in the first year — a reasonable planning figure for a baby who starts at eight to ten changes a day and tapers — a ten-cent gap is a few hundred dollars, which is real money for a difference most families will not notice during daylight hours.
Two caveats on where you buy, both of which cost people money:
The Costco price is the only price the math works at. The warehouse listing is the reference. Third-party Kirkland listings on Amazon exist and are convenient, but they are resold at a markup that can erase the entire advantage over a name brand. Check the per-diaper number before you click, not the sticker.
A membership is part of the cost. If you are not already a Costco member, the first year of diapers has an annual fee attached to it. It still comes out ahead for most families, but it belongs in the calculation rather than in the fine print.
Where it falls down
- Overnights on a heavy wetter. Covered above, and the single most common complaint since the switch.
- No newborn size. The first few weeks need another brand.
- Availability is warehouse-shaped. Sizes go out of stock, and the fix is a drive rather than an app.
- The specification can change under you. That is the lesson of 2025. A private label is a specification a retailer can re-source at any time, and you will find out from your laundry.
- Boxier fit on a slim baby. Worth a single-box trial before you commit to a pallet.
Who should buy it, and who shouldn’t
Buy it if you are a Costco member with a baby past the newborn stage, your priority is the daytime grind, and you want the ingredient exclusions without the premium price. This is the default diaper for a very large number of households and deserves to be.
Buy it with a plan if you have a heavy overnight wetter. Kirkland by day, something purpose-built at bedtime. The blended cost still beats buying a name brand for every change.
Skip it if you have a newborn, if you are not a member, or if you have already tried the current version and watched it fail twice a week. There is no loyalty prize here. If you want the closest cost-competitive alternative, my Hello Bello vs Honest comparison covers the two brands most families cross-shop next, and the Kirkland vs Pampers head-to-head sets the value baseline against the market leader.
FAQ
Are Kirkland diapers still made by Huggies?
No. Kimberly-Clark, which makes Huggies, produced Kirkland Signature diapers until the end of 2024. Costco moved production to First Quality — the maker of Cuties — from January 2025, a change first reported by Bloomberg and widely covered since. The old “Kirkland is just Huggies” shorthand no longer describes what is in the box.
Did Kirkland diapers get worse in 2025?
They got thinner, and a large number of parents report worse overnight performance and more leaks. Costco says the slimmer build is intentional and consistent with where the whole diaper category has moved, and that it found no manufacturing defect. Both things can be true: a thinner diaper that meets its specification can still be a downgrade for your particular baby.
Are Kirkland diapers good for sensitive skin?
They are fragrance-free, hypoallergenic, and made without parabens, phthalates, lotions, elemental chlorine or natural rubber latex, which puts them level with most premium brands on the ingredient list. If a rash persists across a brand change, the cause is usually moisture and change frequency rather than the diaper itself.
How much do Kirkland diapers cost per diaper?
Roughly the mid-teens to low-twenty cents each at Costco, depending on size and box count, against roughly a quarter to thirty-five cents for mainstream name brands. Buy them anywhere other than Costco and that gap narrows or disappears entirely.
What size do Kirkland diapers start at?
Size 1. There is no newborn size, so plan on a different brand for the first stretch, especially if your baby arrives early or small.
Final word
Three and a half stars, down from what I would have given the pre-2025 diaper. Kirkland is still the correct default for daytime changes and still wins the cost math by a wide margin — but it is now a good cheap diaper rather than a name-brand diaper in disguise, and the overnight gap is real enough to plan around. Buy the small box first. Buy it at the warehouse. And do not assume next year’s box is the same diaper as this year’s, because that assumption is exactly what broke in 2025.
