Costco Closed on Labor Day 2021 by Rhonda September 6, 2021 1.3K 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 Black Friday 2026 Ad (Plus Pre-Black Friday... Costco Coupon Book MAY 2026 Costco Coupon Book APRIL 2026 Costco Coupon Book FEBRUARY 2026 Costco Business Center Coupon Book: FEBRUARY 2026 Merry Christmas! 2025