SIMless GrapheneOS plus another phone vs. SIMfull GrapheneOS

I have multiple phones and multiple SIMs for compartmentalisation, including a Personal one (friends & family and instant comms apps), a Spam one (for accounts, outbound calls), a Business one and a Secure one (for banking apps).

My Personal one & Spam one will be securely stored on a benched iPhone at home, but I need to carry my Spam and Business SIMs with me. I

Which model is better?

a) Insert both SIMs in my GrapheneOS phone for simplicity.

b) Have a fully private SIMless GrapheneOS on Airplane mode connected to a portable 5G router. In addition, I’d carry another “normie” phone with no apps just for inbound & outbound vanilla calls & SMS on the Business & Spam SIMs?

I suggest simply making use of different profiles GOS gives you. Your way may work but to me feels overly complicated and unnecessary.

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To have two sims on a grapheneos phone one would have to be esim.

Doesn’t really matter since you’re carrying around the 5G router and second phone anyway. If you were going around with the SIMless phone without the router and second phone, then that’d be better purely from a privacy perspective, but it would obviously come at a serious usability cost.

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Yes, that’s what I meant, eSIM + physical SIM.

I will be leaving my second phone behind outside of business hours. Furthermore, surely a simple 5G router broadcasts less data for harvesting and location tracking than a complex phone with Airplane mode turned off? In 2026, there will be a portable and capable 5G router with WireGuard capabilities released, the benefits I foresee are:

  1. I own a phone whose IMSI, IMEI etc. were never linked to a SIM.
  2. Decreases the number of attributes being harvested more broadly.
  3. Avoids the risk of VPN split-tunnelling (when there are routers that support WireGuard).
  4. Offloads the 24/7 VPN “client” battery drain and improve the longevity of the phone.
  1. This could maybe be useful I guess, but if you’re carrying around the 5G router everywhere, the router is still presumably linked to you. It’d let you use the same phone and swap routers without the cell provider knowing it’s the same phone, although I’m not sure how valuable that actually is. If your phone was somehow taken or something (probably by the government I suppose if they’re matching those identifiers with the SIM) without whoever took it knowing it definitely belongs to you, it’d maybe be slightly harder to guarantee it’s yours.
  2. It’d be slightly better in this regard since they wouldn’t be able to determine device model and so on, but stuff like location tracking would obviously still be possible since you’re carrying around the 5G router.
  3. Might be misunderstanding what you mean here? I don’t think this matters if you’re using GrapheneOS. If the router is using WireGuard, I’d assume all the traffic is going over WireGuard, at which point it seems little different than just blocking all non-VPN connections on your phone?
  4. This could be an actual benefit, although it does mean you have more devices to charge and lug around.

Basically, IMO it’s not worth the hassle. Regarding separate phones, if the identities used for the two phones are separate (or if they’re using different cell providers for whatever reason), then having two phones might be beneficial in the sense that you can leave one at home and that identity wouldn’t be providing useful location data anymore, but if you’re going around with the two devices constantly, they could potentially get linked together (especially if the cell provider is the same), although they might not be able to definitively say they’re both you as opposed to being you and e.g. your child.

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With option B, you would be carrying multiple devices that are linked to you just so that your GrapheneOS phone isn’t. What’s the goal of this compartmentalization method? If it’s to minimize data collection from your phone provider, it might be viable, especially if you can’t get a SIM without KYC. If it’s to minimize location tracking, this would make no difference.

I have a KYC SIM with a permanent number on my “normie” stock Android phone. That’s the number I have for personal use, but I disable all calls and use WhatsApp for calls and messages instead. I use MySudo to compartmentalize my phone numbers and a non-KYC prepaid SIM for data only on my Graphene phone. I download my media files for offline use and turn on my data when I need it, usually when in transit and I turn on airplane mode when I’m near home, work, friend’s house, etc.

Theoretically, my SIM / device isn’t linked to me, so my mobile carrier will get the IMSI / IMEI and location data of my Graphene device, but no PII. I’ve even thought about using my Android phone as a hotspot so that my Graphene phone would be SIMless, but if I end up being a person of interest (for some reason), I think carrying multiple devices would be more risky.

Also, are you able to get VoIP numbers? Is it expensive for you to keep four of your SIMs active?

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I don’t lug around two phones, but I use an iPhone 17 for travel and daily use, and I make all my cellular calls through it. I also have a Pixel with GrapheneOS on it that I use as a pocket computer, connected to home Wi‑Fi. It offers things my iPhone doesn’t, like first‑class VPN support and user profiles. I sync some of my messengers between them so I’m available on both.

It mainly grew out of the need to pass stronger integrity checks rather than GrapheneOS not being able to support the usual use cases. I also have a dumb for phone for SMS verification and other spam. If I could, I would ditch the iPhone today and not think twice about it.

Re compartmentalization specifically, I personally think it’s a bit of overkill. If you can use one GrapheneOS device, just use it for everything. It supports all the meaningful compartmentalization you need. And please don’t use a portable 5G router. Buy a cheap second-hand Pixel 6a/7a instead, install GrapheneOS on it and use it as a hotspot.

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It’s a question of balancing cost and headache:

  1. Contracts or long term prepaid SIMs cost minimum 4-5GBP/month, even with no or low data.
  2. A particular cellular ISP has good promotional rates of around 0.5-1.5GBP/month, but they expire after 5-6 months. Then, to keep your “nice” numbers you need to order a free SIM from another ISP, port your number there and wait for it to settle, get a new SIM with the promotional ISP and port your number back. This is a laborious multi-day process, but so common that it has its own name: “Lebara port dance”.
  3. I use Pay-As-You-Go for my Secure line that only needs to receive inbound SMS, but occasionally torch inactive numbers and I need to remember to do a chargeable activity every 6 months or so.

I’d love it if there was a reliable VoIP service that I can port my “nice” UK numbers to, but I’ve heard they’re all terrible, and might even be more expensive than the aforementioned 5GBP/month/number.

I don’t think another Pixel will work as, per my understanding, 5G hotspot traffic is not routed via the VPN of the phone being tethered to. This is not the case with portable routers. Ideally, I need a 5G router with WireGuard capabilities, I am not sure one exists yet but GL.iNet have Mudi 7 in the pipeline for this year(?).

Have you considered A&A?

No, but which service are you proposing? I need 2-3 numbers to be able to do outbound & inbound calls & SMS. Their SIP2SIM offering looks interesting, but costs ÂŁ10+VAT per SIM.

I know I can do a many : one mapping for inbound calls, but what interface would I use for outbound calls if I port my numbers there?

I’m from the UK as well. So I started with two SIM numbers (for personal and work). I gave up my work number and got a new work number with MySudo since I don’t have as many contacts. Unfortunately, MySudo doesn’t support porting UK phone numbers and porting to other providers (Twilio, Telnyx, etc.) seems like a pain.

So I kept my personal number under Giffgaff because (as far as I know) they have the cheapest way of keeping your number active. You add credit to your account (ÂŁ10) and as long as you use your credit every 6 months (calls, SMS, data), your number will remain active. And that credit should last years!

I would suggest the same thing. Keep your “nice” number and start using VoIP for your other numbers, assuming you can give up your other numbers. You can get 3 different numbers for £10 a month, and if you need data, use a prepaid SIM. That’s ~£20 a month for four different numbers + data.

Why would you need to use their SIP2SIM offering?

They work the same way as other VoIP providers. You can use a ‘soft phone’ for outbound/inbound calls if you want.

We can provide telephones for you, either in the shape of a DECT (cordless) telephone with a base-station that plugs in to your network, or desk phone. You can even use a ‘soft’ phone, which is software on your computer or mobile device.

  • Our Knowledge Base contains articles on helping set up various telephones for use with our service, but typically all you need is the username (your phone number), password and our server. (voiceless.aa.net.uk)

  • Using our broadband service with our VoIP service means you have one port of call and we can help diagnose problems that would otherwise be very hard with other internet providers.

+1 for giffgaff, a really economical way to maintain a bunch of UK mobile numbers. Can be topped up 50 different ways, activated overseas, straight to eSIM or traditional way, used in perpetual roaming mode etc.

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MySudo numbers are significantly more limited than your typical SIM card in other ways too.

Yes, there are limitations, but the numbers are mainly for compartmentalization. You won’t be using them to make traditional calls or text all that often, especially when everyone and their mothers in the UK are using WhatsApp.

That said, I re-read the OP post and they have one SIM for outbound calls. Unless some of the calls are from abroad (or if they have an overseas bank account), the limitations shouldn’t make much of a difference.

I think I articulated it poorly:

  1. Personal needs outbound and inbound calls (so I can call my grandma and she can call me). If I get a call on this number and it is not from someone in my Contacts, I know it’s spam and it gets auto-silenced.
  2. Spam needs outbound and inbound calls (so I can call restaurants, customers service, my GP etc., and vice versa, I give this number for shopping, purchases, accounts. This is auto-silenced during certain hours in the day.
  3. Business needs outbound and inbound calls (so I can call and receive calls about job applications, for instance). Auto-silenced during certain hours.
  4. Secure - only needs inbound SMS from banks, HMRC etc.

I need data on only 1 out of 3, but not even that much.

Unrelated, but I never understood 5G contracts that give you hundreds of GBs per month when the coverage is so poor that you don’t have a viable way to use it. It must be for people that use 5G in lieu of broadband, or they traverse in areas with better coverage than me.

Unless one of the numbers is overseas, the other limitation is MySudo only offers 200 mins a month for inbound and outbound calls. You can get unlimited for £30 a month, but whether this is worth it is up to you. Otherwise, you’ll need at least two other SIMs for spam and work.

As for 5G contracts, some people always want data to stream movies or music. That’s the only reason I can think of.