Costco Closed on Labor Day 2021 by Rhonda September 6, 2021 276 9/6/21. Costco will be closed on Monday, September 6, 2021, in observance of Labor Day. 0 FacebookTwitterPinterestEmail previous post Kirkland Signature Nativity Set at Costco! next post Costco.com Labor Day Sale! 2021 You may also like Costco Unadvertised Sales! JUNE 2023 Solo Stove Mesa Tabletop Fire Pit 3-Pack at... Costco – Memorial Day 2023 Happy Hop Shark Cave Adventure Inflatable Water Slide... Lemon Meringue Cheesecake from Costco’s Bakery! Squishmallows Macaron Lip Balms at Costco!