iPhone XR Dual SIM with eSIM - iMessage and FaceTime

idleauk

macrumors newbie
Original poster
Oct 21, 2009
11
0
In order to avoid extremely high data roaming charges when travelling, I intend to make use of one of the GigSky (or similar) eSIM data packages on my iPhone XR.

All appears relatively straightforward to set up, and https://support.apple.com/en-us/HT209044 provides useful guidance, however I wanted to check the method I will need to use to ensure I do not rack up any data charges when using iMessage and FaceTime.

I will select the following option when choosing the 'default line': "Use Secondary for cellular data only: You might want to select this option if you're traveling internationally and you want to keep Primary for voice, SMS, iMessage, and FaceTime. This will allow you to use Secondary for data." [My underlining]

I find it strange, but this makes it clear that iMessage and FaceTime will still use the primary SIM for their data, which is obviously not what I want to happen. To change the 'source' of data usage for iMessage and FaceTime I believe I will need to change the line that uses iMessage, following these steps:
  1. Go to Settings > Messages.
  2. Tap iMessage & FaceTime Line.
  3. Select the phone number you want to use.
I will have turned data roaming off on the primary SIM before travelling in any case, so no roaming charges should be incurred, however will people still be able to send my iMessages / FaceTime calls in the usual way? GigSky is data only, so no telephone number will be in place for that line. The other option would be to use other services, e.g. Skype.

I will also turn off the iMessage setting "reply with SMS" to avoid any possible charges there.

I also think there should be a clearer warning by both Apple and GigSky that users will also need to switch the iMessage and FaceTime 'line' if they wish to avoid data roaming charges!
 

ravic

macrumors member
Jul 2, 2007
80
7
Yes, what you are suggesting will work.

I have done it recently with Verizon, when I was roaming in Asia with gigsky.

You can switch the "Default Voice Line" and "Cellular Data" to "Gigsky and leave your imessage and facetime on your original providers number.

I switched the lines while I was on the plane. make sure you keep both sims active.
 

idleauk

macrumors newbie
Original poster
Oct 21, 2009
11
0
You can switch the "Default Voice Line" and "Cellular Data" to "Gigsky and leave your imessage and facetime on your original providers number.

I switched the lines while I was on the plane. make sure you keep both sims active.

To be clear is the suggestion that I can use the third option on the 'default line' screen ("use secondary for cellular data only"), and not worry about changing the iMessage/FaceTime line? In essence, will data from the secondary line always be used for iMessage/FaceTime irrespective of which 'line' is set for them?
 

coldwaves

macrumors 6502
May 30, 2011
369
186
To be clear is the suggestion that I can use the third option on the 'default line' screen ("use secondary for cellular data only"), and not worry about changing the iMessage/FaceTime line? In essence, will data from the secondary line always be used for iMessage/FaceTime irrespective of which 'line' is set for them?

I am curious about the same question. Another way to frame the question: can iMessage/FaceTime on one number use data from the other number?
 

xeux

macrumors regular
Jul 19, 2007
162
15
Phoenix, AZ
I am curious about the same question. Another way to frame the question: can iMessage/FaceTime on one number use data from the other number?

Yes you can switch data back and forth while keeping all iMessage and FaceTime settings the same.

I.e I have Verizon and ATT and keep my iMessage and FaceTime line with ATT but switch to Verizon data when camping or traveling in rural areas.
 

coldwaves

macrumors 6502
May 30, 2011
369
186
Yes you can switch data back and forth while keeping all iMessage and FaceTime settings the same.

I.e I have Verizon and ATT and keep my iMessage and FaceTime line with ATT but switch to Verizon data when camping or traveling in rural areas.

Thanks for the info. I guess my question was not expressed very clearly.

To clarify my question, I am not asking whether you can switch which line is used for data. I know that can be changed whenever the user wants to. My question is whether the data on a secondary line can be used for iMessage/FaceTime in the first line. For example, in your case, if you are in an area where AT&T has no data service but Verizon has data service, can you still use FaceTime and iMessage that are associated with your AT&T number?
 
Last edited:

coldwaves

macrumors 6502
May 30, 2011
369
186
Thanks for the info. I guess my question was not expressed very clearly.

To clarify my question, I am not asking whether you can switch which line is used for data. I know that can be changed whenever the user wants to. My question is whether the data on a secondary line can be used for iMessage/FaceTime in the first line. For example, in your case, if you are in an area where AT&T has no data service but Verizon has data service, can you still use FaceTime and iMessage that are associated with your AT&T number?

My confusions comes from reading the Apple supporting documents.

In the apple support documents (https://support.apple.com/en-us/HT209044), it mentions a setting about cellular data switching. There it says "If you turn off Cellular Data Switching and you're active on a voice number that isn't your designated cellular-data number, then cellular data won't work while you're on the call." As I understand, this means that cellular data on a secondary line will not work when the you are on a call in the first line. Since FaceTime is treated somewhat similar as a call in iOS, I am wondering if this extends to FaceTime and iMessage.
 

xeux

macrumors regular
Jul 19, 2007
162
15
Phoenix, AZ
Thanks for the info. I guess my question was not expressed very clearly.

To clarify my question, I am not asking whether you can switch which line is used for data. I know that can be changed whenever the user wants to. My question is whether the data on a secondary line can be used for iMessage/FaceTime in the first line. For example, in your case, if you are in an area where AT&T has no data service but Verizon has data service, can you still use FaceTime and iMessage that are associated with your AT&T number?

Yes, you can. iMessage and FaceTime are data only. In my example, I can use iMessage and FaceTime with my AT&T number via Verizon data if I choose to do so.
 
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monkey28rb

macrumors 6502
Jun 19, 2010
300
13
I am having issues with Dual Sim with Facebook messenger. I am using my primary number for phone/messaging and my secondary carrier for data. When I try and do video messaging/audio messaging, it just says "connecting" for an extended period of time. Sometimes it connects, sometimes it fails.
 
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