Subway, bus, T-money

The default.
Buy at any GS25 / CU / 7-Eleven.
Pay-as-you-go for subway, bus, taxi, and convenience stores.
Most flexible.

Unlimited subway + bus + Han River bus + city bike in Seoul.
1 to 7 day passes.
Cheaper than T-money if you ride 4+ times a day.

T-money + prepaid debit + currency exchange in one.
Reload from a kiosk in 16 currencies.
Useful if you carry cash.

T-money with discounts at attractions, shows, duty-free.
Worth it if you hit COEX Aquarium, Lotte World, or N Seoul Tower.

Incheon T1 / T2 and Gimpo all have CU / 7-Eleven inside the terminal.
Ask for "T-money card", paid in cash or card.
Or grab a Climate Card from the AREX subway counter.

Tap the card on the kiosk, insert cash (₩10,000 minimum is practical).
New 2026 kiosks at 273 stations also accept Visa, Mastercard, JCB, UnionPay, and Amex.
No Korean cash needed.

Tap the card on the gate when you enter and exit.
On buses, tap when boarding and when getting off.
Forgetting the second tap means you pay the max fare next time.

Any GS25 or CU refunds balances under ₩20,000 at the counter (₩500 fee).
For ₩20,000+, refund at the airport T-money counter.
The card itself is non-refundable.
Keep it as a souvenir or save it for next time.

Transfers are free if you tap onto another bus or subway within 30 minutes.
Skip the temptation to pay cash, or you'll lose this discount.

Apple Pay (since March 2024) and Samsung Pay both work on Korean transit terminals.
Your home credit card runs T-money rates if you forget the card.

Subway is fastest.
Korean addresses are weird; subway exit numbers aren't.
When meeting a friend, agree on "Hongik Univ.
Station, exit 9." Always works.