Where to buy the card, how to load it with cash, and where to tap it on the subway, the bus and in a taxi.
At the subway gate there is no ticket slot, only a reader people tap in passing. The card for it is T-money (티머니), a rechargeable fare card in use since July 2004.
Buy one with won in cash at a GS25, CU or 7-ELEVEN, or a station information centre on Lines 1 to 8, for ₩3,000 to ₩5,000; that buys the card, not the credit. Load it, chungjeon (충전), at the counter or a station machine, again in cash: foreign credit cards are not taken. On the subway, hold it to the reader until it beeps, and once more at the exit; on the bus, tap at the front and at the rear door as you leave. Each subway rider needs their own card.
Tapping off earns the transfer: board the next train or bus within 30 minutes, or 60 between 21:00 and 07:00, and the fare is worked out for the whole trip, so the reader may show zero or an extra charge.
In a taxi with the T-money logo, check the balance covers the whole fare, tell the driver you will pay by transportation card, then tap the terminal.