Earlier weekend closing from November
The official visitor pages for Seosomun Main Building, Buk-Seoul Museum of Art, Seo-Seoul Museum of Art and PhotoSeMA each list 10:00–18:00 on Saturdays, Sundays and public holidays from November through February. The corresponding March–October closing is 19:00.
Last entry is not identical
Seosomun (61 Deoksugung-gil), Buk-Seoul (1238 Dongil-ro) and PhotoSeMA (68 Madeul-ro 13-gil) list last admission one hour before closing, or 17:00 on ordinary winter weekends. Seo-Seoul (65 Siheung-daero 79-gil) permits entry until 30 minutes before closing, or 17:30 on those days. These are normal visitor cutoffs, not guarantees for a timed exhibition booking.
Weekdays and closures
Seosomun and Buk-Seoul list Tue–Thu 10:00–20:00 and Friday 10:00–21:00. Seo-Seoul and PhotoSeMA list Tue–Fri 10:00–20:00. All four normally close Mondays and January 1, with a public-holiday exception for Mondays. At PhotoSeMA, the separate photo library closes on Sundays, Mondays and public holidays even when exhibition spaces are open.
Costs and current limitations
Normal admission is free; some special exhibitions at Seosomun and Buk-Seoul have separate charges. Exhibition rooms can have temporary restrictions—for example, Buk-Seoul lists limited access to some spaces October 27–November 5. Always check the specific venue and exhibition notice before departure.