If your smartphone offers the possibility of inserting two SIM cards that's the best, you can switch from your usual SIM to the prepaid travel SIM in just one click. Otherwise, simply replace the current SIM card with your prepaid travel SIM like those available at
www.simoptions.com for instance. This will not change the use of your usual data, applications, social networks, mailboxes and everything else will remain the same.
Make sure your phone is unlocked.
Whatever your decision concerning this SIM card, you will have to have a unlocked phone, i.e. it will have to accept another prepaid SIM card than the one you usually use.
If you bought your phone with an operator package, there is a good chance that your phone will be blocked to the SIM for which it is intended.
On the other hand, phones purchased without commitment and at a high price by users are not affected by simlocking. Their owners remain free to change operator without having to worry about having to perform any unlocking. All they will have to do is change the SIM card so that their device is immediately operational again.
How do I unlock a phone?
The unlocking is perfectly legal most of the time it is free of charge. The majority of operators unlock the phone free of charge after three months of subscription and in the worst case, unlocking is always free of charge after the sixth month of subscription.
If you have to unblock your phone before the legal deadline, the rate varies between €65 and €120 depending on the operator.
Register your contacts on the internet and not on your SIM card!
A basic notion: make sure you never save your contacts only on your sim! At the risk of losing everything if you lose your SIM card. It is therefore essential to make sure that your contacts are saved in Google contacts or iCloud so that you never lose them!
How to synchronize the contacts on your mobile with google contacts?
On Android: When you add your Google account to your Android phone or tablet, your contacts are automatically synchronized.
On Iphone: Open your iPhone (or iPad) settings > Tap "Accounts & Passwords" > Add a Google Account > Enter your email address and password > Enable "Contacts".
How do I sync my iPhone contacts with iCloud?
Settings > Click your name > iCloud > Enable Contacts > Merge