Two phone numbers for messaging apps. Dual SIM required?

[Populus]

Disclaimer: This question is related to messaging apps such as Telegram, Signal, and especially, WhatsApp and the possible requirement of using the Double SIM feature. It also touches a bit on managing eSIM on iOS 17.

I’m tired of waiting for WhatsApp to finally enable Usernames, and because I’m sick of sharing my personal mobile phone number with literally EVERYONE, I’ve decided to get a second phone number. I would like to avoid WhatsApp entirely, but sadly here in Spain that’s not an option. I’ve been almost a year without WhatsApp on my iPhone and I’m literally socially isolated…

The purpose of this new number is to act as a “username” phone number for WhatsApp, Telegram and Signal. And my first and most important question is:

1) Should I enable eSIM on my main number to be able to put the physical SIM card and use the Dual SIM feature? Or it would work without actually putting my SIM card on the iPhone?

On WhatsApp specifically, can I receive the confirming code with that SIM put inside another phone? My goal is to have just the messaging apps working on my iPhone, not the actual phone number itself. If I update WhatsApp, will it require my second SIM to be verified again if it isn’t inside the phone?

1.1) From a privacy point of view, if I install both regular WhatsApp and WhatsApp Business on my iPhone with my personal SIM (and the Business App secondary number verified through SMS with the SIM in another phone), are there privacies issues, namely, will evil META associate my two phone numbers under the same person/profile?

2) Would you have both normal WhatsApp app with your personal phone number and the WhatsApp Business app with the secondary phone number? If this is an option, do I have to install FIRST the personal WhatsApp with my personal phone number, and then the WhatsApp Business app with the second phone number?

3) How does this work on the case of Telegram and Signal? Do they allow two phone numbers? I know that Telegram allows for a phone number and several usernames, but in case I could register both numbers on Telegram, would you do it for ease of management? What about Signal, does it allow usernames? Does it allow two phone numbers simultaneously?

4) In case it is absolutely mandatory to have the SIM card inside the iPhone for WhatsApp to work, I should enable the eSIM for my personal phone number AND put the physical pre-paid SIM on the iPhone. How do you manage eSIM when you perform a restore of the device? I always update my phone through a clean install, so if enabling eSIM disables my physical SIM, and I restore my iPhone, how could I enable the eSIM to have my mobile phone working again? I’ve heard it causes higher battery drain… So as long as I can avoid having both SIMs I’ll prefer it.

That’s all for now, if I see I encounter other difficulties I’ll post here.
Thank you very much everyone.

Bonus track: I’ve been reading that Discord app is a privacy nightmare. If anyone knows an easy and handy way to use discord on my iPhone and iPad, that doesn’t involve installing the official Discord App, it would be great.

 

[ManuCH]

1) you can receive the confirmation number if you have the SIM card in a different phone. Updating WhatsApp will not require your second SIM to be verified again. But if you switch around eSIM settings on your phone, sometimes WhatsApp might pop up a "We detected you have a new phone number" prompt, and it could decide to send you an SMS in some cases. Although it never did for me so far.

1.1) we can never know what META will associate between your 2 phone numbers. They could technically do it. Do they do it? They won't tell us and there's no way of knowing. Officially they probably don't.

2) Yes, I would do it exactly that way and I actually do it that way. And it doesn't matter which one you install first, as WhatsApp asks for the number when installing it (it doesn't just read it from somewhere).

3) Telegram supports multiple accounts with different phone numbers. That's what I did, I run it with multiple accounts. And I also use the Nicegram app (a Telegram clone) to keep things separate.
Signal does now allow usernames, but it does not allow 2 phone numbers simultaneously.

4) A device restore does not erase eSIMs. They survive that. Also Dual SIM doesn't really cause that much of a battery drain, and you can always leave both SIMs in the phone, and just disable one (you can freely turn them on and off as you wish).

Discord app: as every other app, it's sandboxed. It cannot read your data from outside its container unless you allow it. I wouldn't worry about privacy. Just don't give it location permission and you will be fine.

 

[Populus]

1) you can receive the confirmation number if you have the SIM card in a different phone. Updating WhatsApp will not require your second SIM to be verified again. But if you switch around eSIM settings on your phone, sometimes WhatsApp might pop up a "We detected you have a new phone number" prompt, and it could decide to send you an SMS in some cases. Although it never did for me so far.

1.1) we can never know what META will associate between your 2 phone numbers. They could technically do it. Do they do it? They won't tell us and there's no way of knowing. Officially they probably don't.

2) Yes, I would do it exactly that way and I actually do it that way. And it doesn't matter which one you install first, as WhatsApp asks for the number when installing it (it doesn't just read it from somewhere).

3) Telegram supports multiple accounts with different phone numbers. That's what I did, I run it with multiple accounts. And I also use the Nicegram app (a Telegram clone) to keep things separate.
Signal does now allow usernames, but it does not allow 2 phone numbers simultaneously.

4) A device restore does not erase eSIMs. They survive that. Also Dual SIM doesn't really cause that much of a battery drain, and you can always leave both SIMs in the phone, and just disable one (you can freely turn them on and off as you wish).

Discord app: as every other app, it's sandboxed. It cannot read your data from outside its container unless you allow it. I wouldn't worry about privacy. Just don't give it location permission and you will be fine.

Wow, many thanks for your thorough explanation point by point!

Now the 2 decisions I must make are: 1) Having the secondary number on another phone and just use it for the SMS confirmation code, or go and make my main SIM an eSIM and use my iPhone with a dual SIM configuration… although I don’t really need it. And 2) Install both the personal WhatsApp and WhatsApp business or just install one instance of WhatsApp with the secondary phone number…

Then I’ll install Telegram, and Signal. I think I’m gonna start being a bit more social and I need contact apps, even if I still don’t use social networks.

Regarding Discord, I’ll probably use it on Safari. I know it is sandboxed, but I‘ve read nightmarish things on some privacy forums… I guess they were referring to both Android and iOS apps, but as you said, iOS is pretty safe in theory. Still, I think they keep track of your IPs, your devices addresses, and lots of telemetry.

Again, thank you for your long reply!

 

[ManuCH]

Wow, many thanks for your thorough explanation point by point!

Now the 2 decisions I must make are: 1) Having the secondary number on another phone and just use it for the SMS confirmation code, or go and make my main SIM an eSIM and use my iPhone with a dual SIM configuration… although I don’t really need it. And 2) Install both the personal WhatsApp and WhatsApp business or just install one instance of WhatsApp with the secondary phone number…

Then I’ll install Telegram, and Signal. I think I’m gonna start being a bit more social and I need contact apps, even if I still don’t use social networks.

Regarding Discord, I’ll probably use it on Safari. I know it is sandboxed, but I‘ve read nightmarish things on some privacy forums… I guess they were referring to both Android and iOS apps, but as you said, iOS is pretty safe in theory. Still, I think they keep track of your IPs, your devices addresses, and lots of telemetry.

Again, thank you for your long reply!

You're very welcome!

About the SIM card decision, it really depends on what else you're using that secondary number for. I also walk around with 2 phones, the first has 2 SIMs, so yes, everything is possible. And I use both WhatsApp and WhatsApp Business.

Having contact apps is good, I love to be in contact with people. I really think you will like it in the end.

Regarding Discord, in my opinion it will be easier for them to track you if you use Safari, which is the same browser you use for anything else. If you really care about keeping things a bit separate, use a separate browser for Discord, like DuckDuckGo.

Have fun!

 

[Populus]

Specifically about Telegram, can I have different aliases/usernames? Will the different usernames be private, or if someone know one, they will see my other usernames? Can those access my phone number, or it remains private?

Thank you!

 

[ManuCH]

Specifically about Telegram, can I have different aliases/usernames? Will the different usernames be private, or if someone know one, they will see my other usernames? Can those access my phone number, or it remains private?

Thank you!

The only way to have multiple usernames under the same phone numbers on Telegram is by buying them on Fragment. Then you can also choose which ones to show etc, but I never tried that.

Otherwise, you have 1 username for every phone number. That's the standard way. And if someone knows your username, they will only see your phone number if you choose to show it in your privacy settings. The other way around, however, if someone knows your phone number they will always see your main username.

 

[Populus]

The only way to have multiple usernames under the same phone numbers on Telegram is by buying them on Fragment. Then you can also choose which ones to show etc, but I never tried that.

Otherwise, you have 1 username for every phone number. That's the standard way. And if someone knows your username, they will only see your phone number if you choose to show it in your privacy settings. The other way around, however, if someone knows your phone number they will always see your main username.

Interesting… that changes things a bit, so I’ll have to carefully consider my username. And you already said that Telegram doesn’t support two phone numbers, right? Then… I don’t know if I’ll use the burner number or my main one.

From what I see, Fragment only accepts payments in blockchain so… Hopefully I’ll find a good username that isn’t already taken.

 

[ManuCH]

Interesting… that changes things a bit, so I’ll have to carefully consider my username. And you already said that Telegram doesn’t support two phone numbers, right? Then… I don’t know if I’ll use the burner number or my main one.

From what I see, Fragment only accepts payments in blockchain so… Hopefully I’ll find a good username that isn’t already taken.

Telegram does support multiple phone numbers. You can add several accounts to your telegram app and switch seamlessly between them.