Yes, you can absolutely use a Suica card on JR trains, and in fact, it is the primary way most people pay for local rail travel in Japan. Suica is issued by JR East, so it works seamlessly on all JR commuter lines in the Tokyo metropolitan area and beyond. Thanks to the nationwide "interoperability" agreement, your Suica also works on JR lines in other regions (like JR West in Osaka or JR Central in Nagoya), as well as on non-JR subways, buses, and even for payments at vending machines and convenience stores. The only major exception is the Shinkansen (Bullet Train); while you can "link" a Shinkansen ticket to your Suica for paperless entry, you cannot simply "tap" a standard Suica balance to pay for a long-distance bullet train ride, as those require a separate base fare and seat reservation ticket. In 2026, many travelers use the digital version of Suica in their Apple or Google Wallet, allowing them to tap through the gates using just their smartphone or watch.