Unlocking iPhone 6s Sequence

I am traveling over seas for 3 weeks and want to have cellphone access so without paying too much money, I figured unlocking my iPhone would be the best option.

So i've unlocked my iPhone 6s through the carrier (Bell) and I am at the stage where I need to backup, then clear my iphone and finally restore.

I am not taking my laptop with me, so I will not have access to my itunes or any of my music.

My question is, if I do the backup, clear my iphone and then restore now (with my current Bell SIM card), then restore all my media before I travel, when I get to my destination (Australia) can I just swap SIM cards and it should work?.... Or do I need to do the backup, clear and restore with the Australian SIM card ? (which means I will loose a lot of my media when I do an iCloud backup)

Basically do you need to clear the phone and do a restore everytime you swap a different SIM card, or by doing it now before I travel, from here on out can I use any SIM card and not have to worry about my phone?

Thanks guys🙂 Hope my question is clear enough