Korea's public-holiday calendar matters because operating patterns can change even when a city still feels busy. The official VisitKorea holiday guide lists October 3, 2026 as National Foundation Day, October 5 as the substitute holiday, October 9 as Hangeul Day, and December 25 as Christmas, and it also lists the 2027 holiday calendar.

A public holiday is not a universal closure day. VisitKorea's current business-hours guidance says banks are generally open on weekdays and closed on weekends and public holidays, government offices are generally weekday operations, and post offices are also normally weekday services. Department-store hours and monthly closing days vary by store. Treat those as planning patterns, not guarantees for a specific branch.

Museums, markets, restaurants and attractions can follow different rules. Some attractions close on Mondays but open on a Monday public holiday and close the following day; others close on the holiday itself. Always check the facility's own current notice.

Long holiday periods such as Seollal and Chuseok can also affect transport demand. Intercity trains and buses may sell out earlier, road congestion can increase, and some family-run businesses may close while convenience stores and tourist-area businesses remain open.

For any fixed reservation, confirm both the national holiday date and the venue's own operating notice. If a public holiday falls next to a regular weekly closing day, check for a substitute closure as well.