Korean Standard Time (KST) is a time zone that is used in South Korea. It is 9 hours ahead of UTC (UTC+09:00) and is the same as Japan Standard Time, Yakutsk Time, and Indonesian Eastern Standard Time. North Korea observed Pyongyang Time (PYT) (UTC+08:30) starting on August 15, 2015, which was 30 minutes behind KST, until May 5, 2018, when it switched back to KST. South Korea does not observe daylight saving time.