Carrier iPhone 5s locked to AT&T

[Willabak]

Hello, I want to know whether an iPhone 5s that is locked on AT&T can be used outside USA on another GSM network provider without unlocking it please.
Many thanks.

 

[EDH667]

Hello, I want to know whether an iPhone 5s that is locked on AT&T can be used outside USA on another GSM network provider without unlocking it please.
Many thanks.

No it has to be unlocked first to use with another GSM SIM outside of the US.

 

[Applejuiced]

Nope.