Costco Closed on Labor Day 2021 by Rhonda September 6, 2021 476 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 Halloween Candy Deals at Costco! (2024) Costco Closed on Labor Day 2024 Costco Unadvertised Sales! SEPTEMBER 2024 5 Ft Tall Penguin w/LED Lights at Costco! Costco In-Warehouse Hot Buys Sale – AUGUST 2024! Glass Raindrops w/LED Lights at Costco!