Before you fly
Keep the entry checks separate from the packing list.
Check the passport you will actually use
Start with the current entry requirements for your nationality, passport type, purpose and length of stay. Check with the official Korean services or the embassy or consulate handling your application. A friend travelling on a different passport may need different documents. Allow time to resolve questions before the flight.
K-ETA and arrival information
Check whether K-ETA applies to your circumstances, and use the official e-Arrival Card guidance to see whether you must submit arrival information. These are separate checks; do not assume that one application replaces every other requirement. Follow the instructions for the documents you hold.
Make one small offline folder
Save your first accommodation’s Korean address, booking confirmation, onward travel details and insurance contact. Keep sensitive documents protected rather than placing passport copies in a public photo album. Put the hotel address somewhere you can show without opening your entire inbox.
Decide the first journey
Choose a rail or bus route to your hotel before arrival. Note the correct airport terminal and your last connection. You can change the plan after landing, but having a first choice makes the arrival hall less bewildering.