I have not seen any restrictions on people entering Costco at the times I have been there. However I used Google to search for Costco & used Google's estimated number of people shopping at 1 hour intervals. This can keep you from the busy shopping times.
No COVID restrictions. Call the fire Marshall or customer service desk to find capacity restrictions.
No restrictions on how many people allowed.
I am unaware of any restrictions on the number of people entering the store at the same time.
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