There is no way to use your cell phone in outside of your country if it is locked bu your service provider unless they are providing a roaming service for a pretty good price. If you are preparing for a trip and planning to use your cell phone with a different service provider Sim card, it is good to make sure that your phone is unlocked before your trip.
This is the easy way to find out your blackberry phone is locked by your carrier or not.
On your BB phone, Go to Options > Advanced Options > SIM Card Press keys M E P D (not case sensitive)
You will have to “double-tap” the P, so you are actually entering M E P P D
The Network field should say DISABLED. If it says ACTIVE it is still locked.
An Invalid SIM error is often an indicator of a locked phone.