General Information

(1) Debit card will not work at most bank ATMs. Make sure you have a credit card. Most things in Korea do not require cash and can be paid by credit card.

(2) Buy a "T-money" card at a CU, GS25, Ministop or any convenience store and load some money on it. About 20,000 - 30,000 KRW should be enough (~20 euros). Must be paid in cash. This card can be used for public transportation. You tap it on the terminal at the subway gates (or in the buses). If you take a bus, you tap the card when going in and again when leaving the bus.

(3) Download the "Subway" app. It will help you navigate the subway:
Apple | Google

(4) Google Maps does not work well in Korea. Naver or Kakao maps are more appropriate instead:
Apple | Google

(5) Taxis can be called using Uber or Kakao Taxi. You require a Korean phone number to register for Kakao Taxi. At the airport, it is recommended to just line up at the taxi stand:
Apple | Google

More details: Visit Seoul, Official Seoul