iPhone Questions from Android User

Greetings, All,

My wife and I have a "mixed marriage" -- I have only ever had Android phones, and she is an iPhone devotee. We are considering trying out a different cell provider for her, with the possibility of porting her number over if it works just like her current setup. Unfortunately, since I don't "speak Apple" I don't have any experience / expertise in the iOS realm.

Both her current provider, and the one we are considering, are MVNOs that run on the T-Mo network. Her iPhone 7 works just fine right now, even though it doesn't have Bands 66 and 71 that T-Mo uses. Her phone is unlocked (we've confirmed that several times, and the SIM card shows as unlocked) and we have the SIM for the new provider.

I just want to be absolutely sure of a couple of things before we do any SIM changing:
--First, if we remove her current SIM, but she decides that she wants to stick with her current provider after "test driving" the new provider, will we be able to just remove the new SIM, reinsert her current SIM, and her current service will just re-activate fine?
--And second, we realize we'll need to set up voicemail on the new carrier. But will she lose her contacts and texts when we change SIMS back and forth, or do those just stay with the phone regardless of what SIM is in use?

Any advice / insight / experience / expertise you can share would be beyond greatly appreciated! Thanks a million for your help.

I’ve never had an issue on an iPhone using TMo or it’s Mnvo’s and switching back and forth with either. Reactivating was instant and my SMS history remained. AT&T has been a different story.

SIM swapping is fine as long as you're not dealing with Sprint's legacy network.

For the iPhone 7, however, you need to find out if it's an A1660 or A1778. The latter is GSM only, so it won't work on Verizon. Since you mention "test drive", that sounds like the 1-week trial on Mint, which is a T-Mobile MVNO, so it should fine.

If you really want to be safe, make sure you have a recent backup of everything from that phone on iCloud. If any contacts or old messages go missing while SIM-swapping, just factory reset and restore the backup with whatever service you want to use going forward.