Almost everyone who plans a first trip to South Korea runs into the same question: Seoul or Busan, or both? The two cities are only a few hours apart by train, but they feel like they belong to different countries. I lived in Seoul for eight months as an exchange student in 2020, in the student district of Sinchon, and I still go back every year. I have also been to Busan three times, in 2018, in 2020 and again in June 2026, and after my last trip I wrote a complete Busan travel guide. So I have seen both cities as a resident and as a visitor, and my answer depends on how many days you have.