Just as I'm about to get off the bus, the driver says, "Tap your card!" He says. I already tapped when I got on, so again? A foreign student asked, "Are you telling me to pay the fare twice?" He asked. ## Why do you tap when you get off, too? If you tap when you board, it records "I got on here." You have to tap when you get off for "I got off here" to be saved. That's because it needs both places to know how far you've traveled. ## Why Do You Need to Know How Far You've Traveled? Buses and subways in Seoul and the metropolitan area calculate fares by the distance traveled, not by the number of rides. If you go a short way, you pay only the base fare, and if you go far, you pay a little more. So you really need to know where you got off. ## Why is the fare based on distance? The real reason is transfers. People in Korea often switch from a bus to the subway and then to a bus again. If you were charged the base fare every time you boarded, only people who live far away would lose out. So if you transfer within a set time, it's treated as one trip, and only the total distance is charged. Tapping when you get off is a promise that tells the system, "This trip is still going." It's a method designed to be less of a burden even for people who live far away. There's one tip you can use. If you forget to tap when you get off, your transfer may be cut off or you may be charged more. Be sure to tap the reader near the door. Transfer times and fares can change, so check the transit card app or the notice at the stop.