Yangyang County lists Osanri Prehistory Museum opening hours as 09:00-18:00, with last entry at 17:30. Free exhibition interpretation is scheduled to begin at 10:00, 11:00, 14:00, 15:00 and 16:00; each session lasts about 40-50 minutes and explains artifacts and archaeological findings. Groups of 20 or more can request a tour, but capacity may limit availability. Call +82-33-670-2442 to confirm whether the sessions are running and how to book. The tourism page also notes a 470-meter trail by the reeds of nearby Ssangho Lagoon; check local weather and path conditions. Free interpretation does not mean every optional hands-on activity is free.