Use SIM2 data when SIM1 has no signal


I have two SIMs (one is EE and one is O2 [well, Toggle which is Lyca MVNO on O2]). My main SIM is #1 and uses EE. Unfortunately the signal with EE is much worse than O2. I often end up with only O2 signal (SIM #2).

My preferences are “Preferred SIM: EE for data, calls and sms”.

Although data is enabled for both SIMs (4G for EE and 2G for O2) when the signal is lost from EE the Fairphone2 doesn’t seem to automatically switch to using the O2 SIM. The only way I can use the O2 SIM is to go into settings > SIM cards > preferred SIM > Data and change this to O2.

I would expect that the phone would use my preferred SIM (EE) until it had no signal and would then switch to the other SIM (O2) automatically.

Am I misunderstanding the point of dual sim? Please can someone point me in the direction of achieving the automatic switching that I expect.

Many thanks.

That’s a good idea for our feature requests. Currently, it is not possible to automatically switch the data SIM (and the SIM which uses 3G/4G), for example, when the signal is bad, data transfer rate is low or your amount of data is exhausted.

Possible technical limitations if such a feature would be implemented:

  1. You surely want 3G/4G for the SIM which currently uses the data connection. Because 2G is extremely slow. So that has to be switched respectively.
  2. O2 will be longer used than necessary. While using O2, the phone has to interrupt 3G/4G connection regularly to check if EE has 3G/4G.
  3. Unnecessary switching because the connection was lost for only a short time.
  4. Higher battery consumption.

Question to other forum users: Is this possible with Tasker?


I was about to post the same question. I would be very grateful for that feature.
Possibly there could be a setting to select "do you want to switch sim card automatically when there is no signal?"
Or a pop-up “there is no signal on this network. Do you want to switch sim cards?”

1 Like

I have now returned to a single sim, but would still love to see this feature. Sorry I didn’t respond sooner - it didn’t seem hugely important.

Thanks for your thoughts - tofra you raised some good points.

Definitely agree with this. No help just switching the data connection

One could assume that if the signal for the EE mobile network was absent then it wouldn’t interrupt O2 to switch back. If there was mobile network then it would try switching and if internet failed then there could be a popup along the lines of “Continue with O2 data?”. The phone could then try again in x minutes. I don’t know if it is very common to have a mobile network signal, but no data connection, and the Fairphone seems to be able to keep up to date with which networks have signal.

Possibly a slight delay after the signal reappears could prevent really frequent interruptions in weak connection areas. The phone would have something like a double-knock limit - if the signal (As per thought 2 above) remains connected for 30 seconds, then try switching. This would get rid of the signal for 1 second, phone tries switching only to find signal gone again.

I would expect this to be minimal if it is only reading the information from the connections available, rather than continuously disconnecting and polling the connections.

I guess this topic has either disappeared off people’s radars, or we’re the only 3 interested in it!!

Do we need to post it to feature requests?

It can be posted at the feature requests if there is at least one user who wants that feature. You don’t need a minimum number of interested users. It’s more like an “idea collection pool”.

The number of users who want that feature will be determined by the number of likes.

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