Parents with a Costco membership always look forward to the semi-annual Kirkland diaper sale in June and November, but with recent supplier changes in 2025, it looks like they're switching up the sale schedule too.
As of the third week of June, we still haven't seen a Costco diaper sale pop up as expected this month. In prior years, the sale could save you $9 per box (around 20%), and those savings added up fast if you bought multiple boxes. And just like the deals in the Costco Coupon Book, the discount applied automatically at checkout.
But now that they've skipped the June sale, here what we're predicting after tracking Costco deals and sales for years.
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The Costco Diaper Sale is typically a twice-a-year, 14-day event that knocks $9 off each box of Kirkland diapers automatically.
Costco has historically run this sale twice yearly, once in June and again in November. But it looks like 2025 isn't following the typical sales pattern. The $9 discount typically applies to all sizes of Kirkland Signature diapers, currently priced at $39.99 for sizes 3 and up, $19.99 for size 2, and $14.99 for size 1. Savings happen instantly at checkout, no coupons required.
But since Kirkland diapers recently switched manufacturers (from Kimberly-Clark to First Quality, the maker of Cuties diapers) and has changed box sizes and prices, the discount structure might change this year.
KCL predicts the next Costco Diaper Sale will happen Nov. 10 - 16, 2025.
Costco doesn't announce their diaper sale in advance, but based on past patterns, we predict the next one might pop up Nov. 10 - 16, 2026.
We fully expected to see one start the first week of June 2025, but that didn't happen as predicted.
How do we make our prediction?
Our team at The Krazy Coupon Lady has tracked the Costco diaper sale pattern for years. Here are the most recent sale dates to give you an idea of the schedule:
June 3 - 16, 2024
No sale in November 2024, likely due to the manufacturer switch
June 5 - 28, 2023
Nov. 13 - 19, 2023
Sept. 28 - Oct. 23, 2022
March 25 - April 3, 2022
Claim the same sale prices online or in-store — diapers don't have an online markup.
Unlike many of the items you can buy from Costco online, there's no online markup on diapers, meaning that the price you see for diapers on Costco.com is the same low price you'll pay in the warehouse. Plus, shipping is free on Costco diapers.
There's usually a daily limit of two boxes per size, per transaction.
Costco typically limits diaper sale purchases to two boxes per size, per membership, per day. This means you could buy two boxes each of sizes 3, 4, and 5 in one trip. And since it's a daily limit, you could make multiple trips during the sale if needed.
Terms may change with the new supplier, so we'll be sure to confirm the details when the next sale goes live.
KCL TIP: Need more boxes than the limit? Ask friends with a Costco membership to help you stock up.
Buy enough to last you 6 - 12 months, as the sale only happens once (or twice) a year.
Since this sale only comes around once every 6 - 12 months, it's a good chance to stock up if you like the Kirkland brand diapers. Just calculate your monthly diaper usage and multiply that by six (or 12).
Here's a list of the current diaper counts per box:
Size 1: 96 diapers per box
Size 2: 112 diapers per box
Size 3: 222 diapers per box
Size 4: 198 diapers per box
Size 5: 168 diapers per box
Size 6: 132 diapers per box
Ask for a price adjustment if you bought full-price Kirkland diapers within 30 days of the sale.
Recently bought Costco diapers at full price? The Costco price adjustment policy gives you money back if an item goes on sale within 30 days of purchase.
For in-store purchases, just visit the Returns desk with your membership card (no receipt needed) to get a refund for the price difference. For online orders, fill out Costco's price adjustment form on their website.
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