Just weeks after announcing its impending breakup with American Express, Costco has moved on to a new credit card partner. Starting in April 2016, Visa will be the only credit card that Costco accepts. Also on the way out is the the Costco American Express TrueEarnings card, which will be replaced next year by a co-branded Costco Visa. Still to be determined: whether that new Visa card will offer the same level of generous cash-back rewards.