The Suica card can be used for most major transit and retail transactions in Japan, but it is not universally accepted everywhere. While it works seamlessly on almost all trains, subways, and buses in the major metropolitan areas of Tokyo, Osaka, Kyoto, Nagoya, Sapporo, and Fukuoka, there are still rural areas and smaller private rail lines where it is not supported. For example, you cannot use a Suica for "continuous travel" between different regional zones (like taking a local train from Tokyo to Nagoya). It is also not valid on the Shinkansen (bullet train) unless you specifically link it to a pre-paid "Smart-EX" reservation. In terms of shopping, it is widely accepted at convenience stores (Konbini), vending machines, and many restaurants nationwide. However, in 2026, some smaller independent shops in the countryside still prefer cash. For a tourist, the Suica (or the "Welcome Suica" for short-term visitors) is the only card you'll need for 95% of a standard urban itinerary.