How to Actually Save Time on a Trip to Korea

Buy your SIM/eSIM online before you arrive so you're online the moment you land, instead of waiting in an airport activation line.
Pre-register for unmanned automated immigration alongside K-ETA — the electronic gates have a much shorter line than staffed counters.
Book popular restaurants ahead through apps like CatchTable or Naver Reservation — showing up and hoping for a walk-in spot often means losing over an hour.
AREX, the airport railroad's express train, is the fastest and most predictable way into the city — far quicker than a limousine bus during rush hour.
Buy attraction tickets in advance as QR codes through Klook or Trazy — often lets you skip the on-site ticket line entirely.
Kakao Map and Naver Map both show real-time bus arrivals, so you can time your walk to the stop instead of waiting around blindly.
Restaurants near concert venues get busiest 2-3 hours before showtime — eat earlier in the afternoon instead and skip the wait.