【 iOS Device】

「settings」➔「General」➔「About」➔「Carrier Lock」 ➔No SIM restrictions

【 Android Device】

You cannot determine this directly from the mobile phone. Please check with the place of purchase or the carrier you have a contract with.
SIM lock regulations vary by country. In Taiwan, most phones are not SIM-locked.Devices purchased in countries like Japan or the United States are more likely to have SIM lock issues.
📢If you have used SIM cards from different countries or carriers, the device is likely not SIM-locked.