1 Solution
Accepted Solutions
You should be able to simply dial the numbers from your phone so their is no reason to change your sim card if your intending to use any roaming options your mobile network provides.
May I add 》 What you would need to do is check with your UK Network as to what Roaming options and agreements they have in the country to wanting to visit.
Look at the costs to roam and what your contract with your network allows.
Also check any roaming bars have been de activated.
Now what some people do @john36 is to have their phone unlocked to all networks if it's locked in the first place so they can insert a local sim card when they arrive into the country they are visiting.
They do this because sometimes it's cheaper to do this than use their own networks sim card or the signal is poor etc.
If the phone is locked to your network then have a look on your networks home page / support pages and there should be assistance to have the phone unlocked to all networks.
Hope that helps.
Enjoy your trip. 
You should be able to simply dial the numbers from your phone so their is no reason to change your sim card if your intending to use any roaming options your mobile network provides.
May I add 》 What you would need to do is check with your UK Network as to what Roaming options and agreements they have in the country to wanting to visit.
Look at the costs to roam and what your contract with your network allows.
Also check any roaming bars have been de activated.
Now what some people do @john36 is to have their phone unlocked to all networks if it's locked in the first place so they can insert a local sim card when they arrive into the country they are visiting.
They do this because sometimes it's cheaper to do this than use their own networks sim card or the signal is poor etc.
If the phone is locked to your network then have a look on your networks home page / support pages and there should be assistance to have the phone unlocked to all networks.
Hope that helps.
Enjoy your trip.
