Should you add Jeju to your first Korea trip?
Jeju can be a great island segment, but it adds another flight, two airport transfers and more sensitivity to weather and timing.
Quick answer
Add Jeju when you have enough nights to treat it as a separate part of the trip. Skip it when doing so would force Seoul, Gyeongju or Busan into rushed one-night stops.
You want island landscapes, have room for another flight segment and can keep some flexibility around weather or transport.
Your Korea trip is short, you dislike frequent hotel changes or you would rather explore Seoul and the mainland at a slower pace.
The real cost is not only the domestic airfare. Count airport access, check-in, waiting time and the activities you give up elsewhere.
Jeju should earn its place in the itinerary. Add it when the island experience is more valuable to you than the mainland time it replaces.
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