Katie Broome | 

Costco's Semi-Annual Diaper Sale Should Return in June — Look for $9 Off

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Parents with a Costco membership, get ready to save because the semi-annual Kirkland diaper sale is likely coming up soon. Based on past Costco diaper sales, we expect you'll save about $9 per box (around 20%) during this 2-week event. These savings can add up fast if you're buying multiple boxes, and the discount applies automatically at checkout. And just like the deals in the Costco Coupon Book, no coupons are actually required.

We've tracked Costco deals and diaper sales for years, and we've noticed Costco typically follows a pretty consistent pattern. But with recent supplier changes, we might see a few differences this time around.

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The Costco Diaper Sale is a twice-a-year, 14-day event that knocks about $9 off each box of Kirkland diapers automatically.

Costco has historically run this sale twice yearly, typically in June and November. The $9 discount 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.

Note that Kirkland recently switched from Kimberly-Clark to First Quality (the maker of Cuties diapers) and has changed box sizes and prices, so the discount structure might change this year.

KCL predicts the next Costco Diaper Sale will happen June 2 - 15, 2025.

Costco Diaper Sale predicted start date of June 2, 2025

Costco doesn't announce this sale in advance, but based on patterns, we predict the next one will happen June 2 - 15, 2025.

After the June event, the next Costco diaper sale likely won't happen until Nov. 13 - 19, 2025, so it could be worth stocking up on enough diapers (and sizes) to last you for six months.

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:

  • 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.

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 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 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 six months, as the sale only happens twice a year.

costco-kirkland-signature-diapers-1

Since this sale only comes around once every six 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.

Here's a list of the current diaper counts 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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