Will all merchants accept Samsung Pay?
Samsung Pay uses proprietary technology that works with both Magnetic Secure Transmission (MST) used to swipe cards and Near Field Communication (NFC) to make contactless mobile payments. MST and NFC enable the Galaxy S6, S6 active, S6 edge, S6 edge+ and Note 5 to make transactions at most card readers where you can swipe or tap your card, excluding gas station pumps.
Please continue to carry your physical cards to use where Samsung Pay is not accepted. Most merchants will display the contactless payment symbol to let you know they accept contactless payments. You can visit this website to determine terminals that accept Samsung Pay http://www.samsung.com/us/samsung-pay/