Seoul operates a network of late-night N-buses for the hours when ordinary subway and bus service is limited. The city's 2026 holiday transport guidance says 14 night-bus routes operate as usual from 11 PM to 6 AM daily.
Do not plan from an old static route table alone. Before leaving a restaurant, concert or bar, open Seoul TOPIS and confirm three things: the N-route that actually serves your destination, the correct stop and direction, and the current arrival time. A night bus can be useful only if its corridor matches where you are going; a taxi may still be the practical fallback for the final leg.
Holiday notices can temporarily extend subway or regular-bus service, but those extensions are date-specific. Treat them as exceptions rather than the normal timetable.
Practical sequence: check the last subway first; if you will miss it, search the destination in TOPIS; identify the exact N-bus stop and direction; keep a taxi fallback if the final stop is far from your lodging. Recheck the route at the time of travel because late-night service is operationally volatile.