Starting tomorrow, June 20, 2016, Visa is taking over as the exclusive credit card for Costco, which means all other non-Visa credit cards will no longer work.
Note, you do not need to use the Costco-branded Visa card. Other Visa cards will be accepted. You can also still pay with cash, checks, debit cards, Electronic Benefit Transfer (EBT) and Costco Cash Cards.
For 16 years, Costco warehouses in the United States had accepted only American Express cards. But last year, American Express announced that its cards won’t be accepted at Costco anymore, because the two companies couldn’t agree to the terms of a new deal.