Yes, funds on a physical Suica card (the Japanese transit and payment card) do expire, but only after a very long period of inactivity. According to JR East rules for 2026, a Suica card remains valid for 10 years from the date of its last use. If you do not tap the card for a full decade, the card becomes "invalidated." However, even if this happens, you can often take the physical card to a JR ticket office in Japan to have the balance transferred to a new card, though a small processing fee may apply. This rule applies to the standard "Green" Suica cards. The "Welcome Suica" (the red card designed specifically for short-term tourists) is different; it has a strict 28-day expiration date and any remaining balance is non-refundable, making it essential to spend your balance before leaving the country.