Update March 2017: Discover has become nearly unusable in China. If you do not have the newer chip version you may experience success, however the chip cards are rejected at almost all merchants except those that otherwise accept many foreign credit cards. I have repeatedly sent feedback to Discover and gotten no helpful response. One representative said sometimes in her experience terminal require 3 failed attempts with a chip before accepting the magnetic strip swipe. Fat chance getting someone to swipe over and over in China!
Discover and China’s UnionPay have reciprocal deals to allow their cardholders access to the other’s payment network. I had forgotten about this until reminded by a Businessweek article on state-bank backed UnionPay, with its strangle-hold on China, has the #2 place in global credit- and debit-card transaction volume at 23.8%, trailing only Visa. In China, UnionPay gets a cut even of American Express, MasterCard and Visa transactions. The article did not provide UnionPay’s global ex-China position.
‘Foreign’ (non-China issued) card acceptance in China is still quite low. A merchant may have Visa and MasterCard logos on display, but that may only apply to China-issued cards. Some merchants may in theory accept foreign cards yet claim their machine just happens to be broken, or try to add a surcharge. Generally the answer is just a ‘no.’ Foreign cards are only reliably accepted at high-end international brand hotels, fairly common at high-end restaurants in major cities, and some retail, like Carrefour and Walmart. Some of the online travel websites now accept foreign credit cards with less hassle than a few years ago when fax authorizations and such were required.
Discover’s partnership with UnionPay promises to solve this, their cards accepted by any UnionPay card reader, and Discover does not charge foreign transaction fees. I specifically say card reader, and not merchant, because virtually no one in China knows the Discover brand and Discover cards do not display the UnionPay logo familiar to Chinese. Reader Andrew R commented of his difficulty convincing Chinese merchants to accept his Discover card. I was in Shanghai two weeks ago but did not have a Discover to test.
I searched UnionPay’s website for information on Discover and found little of use to print out and show to Chinese merchants. Discover, though, clearly has dealt with this difficulty and has a handy Chinese-English print-out card. I strongly recommend you show this card anytime you try to use Discover in China.
Discover has a Country Acceptance Map, and an Asia FAQ. In addition to China with UnionPay, Discover is accepted in Japan at JCB locations, and Philippines, Singapore, South Korea, Taiwan and Thailand at Diners Club International locations.
I have not extensively traveled Japan in some years so not sure if foreign card acceptance is much of an issue. The other countries I have traveled more recently and my experience is that if a merchant accepts Diners Club International then they also will accept Visa and MasterCard. American Express coverage is always spotty.