Apple’s Find My will track down a lost iPhone anywhere, unless you’re in South Korea, or if your phone was made there.
National Assembly of the Republic of South Korea
National Assembly of the Republic of South Korea
All iPhones made to be sold in South Korea have Find My permanently disabled. Not only won’t it work in the country, but Find My can’t even be used if you take your South Korean iPhone overseas.
Similarly, the block also applies to iPhone users visiting the country. While iPhones made everywhere else do include Find My, it’s disabled once they are taken into South Korea.