Dual SIMs / eSim and preventing data use on primary SIM

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timmmay

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#316141 19-Sep-2024 18:14

I'm going to the UK later in the year, I'm going to get a GiffGaff esim. I'd like to prevent using any data or calls on my NZ sim in my Pixel 8 and my wife's S22. This Google page says you go into settings and set which SIM you want data / calls / messages to use. Is it that simple? Are there any gotchas? I'll keep the phone in Airplane mode with WiFi on until I have the eSim set up, which I'll purchase and install in Healthrow or the hotel using their WiFi.

Handle9

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#3284177 19-Sep-2024 18:26

If the SIM is active it can receive calls. I don't think there's a way around that.

If the SIM is active you select a default calling SIM but this can be changed when making a call.

If you disable data on a SIM it's off for data and can't be used for that.

timmmay

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#3284186 19-Sep-2024 19:12

Thanks Handle9, you reminded me to look into the settings. I can disable the SIM entirely, disable roaming data or mobile data, disable 4G calling, and WiFi calling works. I think simply disabling the SIM should do the job.

tardtasticx

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#3284254 19-Sep-2024 21:15

Firstly these below details were from an iPhone so might vary for your android devices slightly.

Easiest way is while you’re in NZ go to mobile settings and turn of Automatic Network Selection.
When the list of networks come up, select your NZ telco and it’ll attach to it just fine.
While in NZ you wont notice any difference at all.

The magic is when you land in another country, your phone is still trying to attach to the network you manually selected. Since it doesn’t exist overseas obviously, it will fail to connect and wont get any service. Since automatic selection is turned off as well it wont even attempt to connect to another network to establish roaming. Most of the time (see below) it’ll just show no service on that SIM.

Then you can add any other SIM you like, and leave the settings on that new SIM as defaults. The automatic network selection is unique to each SIM, so your primary one has this off while the secondary has it turned on. Then set the secondary SIM as your data SIM and you’re good to go.

If you’re on OneNZ or 2Degrees, while overseas you can use WiFi Calling. I assume androids would do the same, but the SIM which isn’t used for data will use the second SIMs data connection to establish wifi calling connectivity. So you can use your NZ SIM in another country over mobile, but that SIM behaves as if it was in NZ using WiFI calling.

We’ve done this in Australia and Scotland, has worked perfectly each time for our OneNZ SIMs with a local eSIM for data.

timmmay

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#3284267 19-Sep-2024 21:45

Thanks @tardtasticx that's very useful 🙂

Asteros

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#3284270 19-Sep-2024 21:59

tardtasticx:

Firstly these below details were from an iPhone so might vary for your android devices slightly.

Easiest way is while you’re in NZ go to mobile settings and turn of Automatic Network Selection.
When the list of networks come up, select your NZ telco and it’ll attach to it just fine.
While in NZ you wont notice any difference at all.

The magic is when you land in another country, your phone is still trying to attach to the network you manually selected. Since it doesn’t exist overseas obviously, it will fail to connect and wont get any service. Since automatic selection is turned off as well it wont even attempt to connect to another network to establish roaming. Most of the time (see below) it’ll just show no service on that SIM.

Then you can add any other SIM you like, and leave the settings on that new SIM as defaults. The automatic network selection is unique to each SIM, so your primary one has this off while the secondary has it turned on. Then set the secondary SIM as your data SIM and you’re good to go.

If you’re on OneNZ or 2Degrees, while overseas you can use WiFi Calling. I assume androids would do the same, but the SIM which isn’t used for data will use the second SIMs data connection to establish wifi calling connectivity. So you can use your NZ SIM in another country over mobile, but that SIM behaves as if it was in NZ using WiFI calling.

We’ve done this in Australia and Scotland, has worked perfectly each time for our OneNZ SIMs with a local eSIM for data.

This is really good! Were your One NZ Sims Prepay or Pay Monthly?

timmmay

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#3284272 19-Sep-2024 22:08

One has unhelpfully changed the network name to "Kia Ora" for Maori language week. It made selecting the network manually more confusing than it needed to be.

One NZ, please stop changing your network name.

Goosey

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#3284307 20-Sep-2024 06:59

timmmay: One has unhelpfully changed the network name to "Kia Ora" for Maori language week. It made selecting the network manually more confusing than it needed to be.

One NZ, please stop changing your network name.

errr, that happens every year and you should have already noticed that at the start of the week?

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timmmay

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#3284309 20-Sep-2024 07:02

Goosey:
timmmay: One has unhelpfully changed the network name to "Kia Ora" for Maori language week. It made selecting the network manually more confusing than it needed to be.

One NZ, please stop changing your network name.

errr, that happens every year and you should have already noticed that at the start of the week?

My phone doesn't show the network name. The closest it gets is if I pull down twice I can see "Vodafone NZ Wi-Fi calling" scrolling at the top of the screen.

tardtasticx

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#3284311 20-Sep-2024 07:10

Asteros:
tardtasticx:

This is really good! Were your One NZ Sims Prepay or Pay Monthly?

We’re on OneNZ pay monthly - but I understand from OneNZs site that wifi calling works overseas on both prepay and paymonthly plans. So steps should be the same for both hopefully.

We did notice one of the iPhones didn’t have wifi calling on by default on the phone settings, so just check for that I guess.

quickymart

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#3295331 10-Oct-2024 09:30

eSIMs aren't necessarily the be-all and end-all though...

https://www.nzherald.co.nz/nz/familys-plea-after-kiwi-woman-kaya-awhitu-disappears-holidaying-in-bali/R5OBK36TIRDDZECEPZKSAXKR2Q/

“She got an eSIM card and she’s been hacked. Her whole phone has been taken over and she can’t log in.”

I think I'd stick with my old-school SIM if I was travelling overseas...

lxsw20

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#3295332 10-Oct-2024 09:33

My bet is that has zero to do with the fact its an eSim vs physical.

Asteros

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#3308993 14-Nov-2024 14:59

tardtasticx:

Firstly these below details were from an iPhone so might vary for your android devices slightly.

Easiest way is while you’re in NZ go to mobile settings and turn of Automatic Network Selection.
When the list of networks come up, select your NZ telco and it’ll attach to it just fine.
While in NZ you wont notice any difference at all.

The magic is when you land in another country, your phone is still trying to attach to the network you manually selected. Since it doesn’t exist overseas obviously, it will fail to connect and wont get any service. Since automatic selection is turned off as well it wont even attempt to connect to another network to establish roaming. Most of the time (see below) it’ll just show no service on that SIM.

Then you can add any other SIM you like, and leave the settings on that new SIM as defaults. The automatic network selection is unique to each SIM, so your primary one has this off while the secondary has it turned on. Then set the secondary SIM as your data SIM and you’re good to go.

If you’re on OneNZ or 2Degrees, while overseas you can use WiFi Calling. I assume androids would do the same, but the SIM which isn’t used for data will use the second SIMs data connection to establish wifi calling connectivity. So you can use your NZ SIM in another country over mobile, but that SIM behaves as if it was in NZ using WiFI calling.

We’ve done this in Australia and Scotland, has worked perfectly each time for our OneNZ SIMs with a local eSIM for data.

Hi I'm using an Iphone on One NZ Pay Monthly. I have disabled One NZ Roaming. To get wifi calling working using local data using your method above, do I need to enable "Allow Mobile Data Switching" in the Mobile Data Setting choosing between the two eSims (One NZ and local data)? Or do I just set the data sim as the local SIM and don't enable Mobile Data Switching? Thanks

wellygary

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#3309012 14-Nov-2024 15:39

Does anyone know if there is a way to only allow the One NZ sim to receive only?

Doing a similar UK trip at the end of the year, Will def get local sim or esim, but was hoping to see if there was a E-sim solution with a way to keep the OneNZ alive to receive things like VISA 2FAs etc ?.

Asteros

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#3309071 14-Nov-2024 19:17

I've done some testing. Can confirm this works using previous settings described above.

TLDR One NZ Wifi calling on a foreign sim (with data) works overseas! - i.e. don’t need to go into Airplane mode and connect to a foreign Wifi hotspot or foreign Wifi network. You can make and receive calls and send and receive SMS as if you were on Wifi in NZ, but running on foreign 4g or 5g networks.