In 2026, the Japan Rail Pass (JR Pass) counts validity based on consecutive calendar days, not 24-hour periods. If you activate your 7-day pass on a Monday at any time (even as late as 11:59 PM), that Monday counts as Day 1. The pass will then be valid for the remainder of that day and the following six days, officially expiring at midnight (23:59) on the seventh day. For a Monday start, your pass would expire at the end of the following Sunday. If you happen to be on a train when the clock strikes midnight on the final day, the pass remains valid until you reach your final destination, provided you do not pass through a ticket gate at an intermediate station. This calendar-day system makes it crucial to activate the pass early in the morning on your first day of travel to maximize its value.