Costco Closed on Labor Day 2021 by Rhonda September 6, 2021 646 9/6/21. Costco will be closed on Monday, September 6, 2021, in observance of Labor Day. 0 FacebookTwitterPinterestEmail previous post NEW Kirkland Signature Nativity Set at Costco! next post Costco.com Labor Day Sale! 2021 You may also like Costco Coupon Book APRIL 2025 Costco Business Center Coupon Book: APRIL / MAY... Costco Hot Buys Sale: 3/29/25 – 4/6/25 Permasteel 46″ Rolling Work Bench at Costco! Bond Bloomington Cascading Cup Fountain at Costco! Costco Unadvertised Sales! MARCH 2025