Jeju is overwhelmingly reached through Seoul or Busan rather than direct international flights, which makes Korea's own domestic holiday calendar the single biggest factor in what you'll pay.
The cheapest months to fly
Late autumn (November) and winter (December through February, outside the New Year period) tend to offer the lowest domestic fares into Jeju, since demand drops once the mild shoulder seasons pass. Early June, just before the summer break and typhoon season ramp up, can also be good value.
How far ahead to book
Domestic Korean routes to Jeju are dense and competitive, so 3 to 6 weeks ahead is often enough for a reasonable fare outside major holidays. If your trip lines up with Chuseok, Seollal (Korean New Year), or the peak of summer break, book 2-3 months ahead instead — these periods see some of the heaviest domestic travel demand in the country.
Watch out for these price spikes
- Chuseok, Korea's autumn harvest holiday (a multi-day break that falls September 24–26 in 2026, with many workers extending it further) — one of the two biggest domestic travel surges of the year, with Jeju a top destination for it
- Seollal, Korean New Year (also lunar-calendar based, typically January or February) — the other major domestic holiday surge
- July and August school summer holidays, which combine with typhoon-season uncertainty
A few practical habits that help
Jeju International Airport (CJU) connects most heavily to Seoul's Gimpo (GMP) and Incheon (ICN) airports and to Busan (PUS), so if you're flying in internationally, expect to land in Seoul or Busan first and connect onward — very few direct international routes serve Jeju itself. Domestic Korean carriers, including several low-cost airlines, compete heavily on the Seoul–Jeju route specifically, so comparing several rather than booking the first result tends to pay off.
The short version
November and quiet-winter dates (outside Seollal) offer the best value. Book a few weeks ahead for most travel, but move to 2-3 months out if your dates land near Chuseok, Seollal, or peak summer — Jeju's domestic holiday surges are sharp and predictable once you know when they fall.