Other iPhone Dual Sim Capabilities


macrumors newbie
Original poster
Sep 11, 2018
Hi everyone!

Just curious to those people who have two phones like I do, how will dual sim work exactly? Both of them are iPhones and would be great to have iMessage for both, but the website doesn't really specify the nitty gritty details of the usage. It mentions that the second line is only for SMS and call and didn't mention anything about iMessage.


It's great that they are starting to use this dual sim technology, because I don't have to keep carrying two separate phones. Any clarification would help!



macrumors 6502a
Jul 5, 2010
Los Angeles
So I read it the same way, only the line you designate as primary has iMessage. From there they appear to give you some simple overall preferences primary/secondary/voice/data. I don’t expect they’ll give you app level preferences ever to keep it simple for end users (not like Android has). I can only assume that iMessage being the primary line only has to do with how they implement it and make it so sticky. Prior to dual sim, anytime I swap in a new sim I have to ensure I turn off iMessage and FaceTime to deregister it from the sim/number i’m taking out (this process repeats evertime) this ensures I don’t get any numbers locked in to my iMessage account I don’t want to keep. I have to assume this is why apple is limiting it to the primary number as well. Most users won’t be technically inclined enough to know how this works, they’d end up with numbers associated with their iMessage that they not longer have etc. it’d impact apples user experience and simplicity that they care so much about.

Dual sim was a huge selling point to me this year. Between a personal and work work line and using local sims when traveling this will be super convenient.
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macrumors regular
Sep 24, 2012
iMessage has no physical link to the device or SIM, it’s only based on a phone number (having a SIM associated with that number “proves” it’s you to Apple).

So I expect iMessage *could* work on both numbers.

I think Apple doesn’t spell that out along with SMS because iMessage is just software. SMS works at the carrier/modem level.

Brown Trout

macrumors member
Mar 6, 2011
Slightly different dual sim question. I ordered the Xs thru the Apple store app, and just had the existing, long-term ATT plan carry over. I’ll pick it up at the nearby physical store sometime in early Oct.
  • If one sim in Xs is an eSim, will my exiting carrier - ATT - use that one?
  • If thats the case, if I want to use a nano sim (which I have now in an unlocked 6 the Xs replaces) e.g. for travel to the UK, will the Xs be unlocked for the nano when I pick it up or do I have to go thru ATT?
I know I had the option to buy unlocked. If I did it that way, then I thought plugging the existing sim in the nano would mean using eSim in the UK.

Probably overthinking this but the net question is probably off topic: how long does it take to unlock via ATT currently if you’ve satisfied the contract & does it matter whether or not you have a new phone//TIA

edit: I think I have the unlock answer..
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macrumors 6502a
Sep 14, 2007
Your device has to be completely unlocked for dual sim to work properly.
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