Mobile data usage while connected to WIFI (FP4)

I’ve been experiencing some serious issues with mobile data usage while also connected to WIFI.
The OS seems to prefer using mobile data over WIFI, so for the past three months I ran out data long before the end of the month. This always happens when I’m at home or work. Both my home and work have a stable WIFI network and descent coverage throughout the house and office. With my previous phones I’ve never experienced anything like this. Neither does my wife. She doesn’t use /e/ OS btw.

  • Phone: FP4
  • e/ OS version: both 1.0 and 1.1
  • VPN: NordVPN

I have just installed v1.2, so I don’t now yet if the problems still occurs, but I did ran out of data again by downloading v1.2 while at home and connected to WIFI :frowning:

Two questions:

  1. Are there more users experiencing these kind of problems?
  2. Any suggestions to solve this problem?


Would be good to know the apps causing this traffic. You could install an app like Traffic Monitor (Trecone Solutions) to analyze this.

What happens if you switch this VPN off?


I have also experienced that the phone can seem to prefer mobile over wifi.

You may have to take action app by app. In the case of the System updater, this setting can be set from

Settings > Apps and notifications > See all … apps > top right 3 dot menu > Show system → Use search feature for Updater (may have different name) > Mobile data & WiFi

Also worth setting a Data limit and warning to help alert you to when this happens.

Settings > Network an internet > Mobile network > Data warning and limit.


It was NordVPN that used up all the data, but this was obviously caused by the downloading the system update.

I haven’t tried using my phone without NordVPN enabled. I could try that, but that would defeat the purpose of a VPN. Besides I haven’t experienced this problem with NordVPN on my previous android phones.

Thanks! That could be helpful, but doesn’t address the cause of the problem.

I shall set the data limit to a lower value, so I will be warned before my mobile data runs out.

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I am experiencing the same on FP3+ with v1.0 and 1.2.
Last time was today when I updated Threema.

If not done already, make the Developer options visible by tapping on the Build number in Settings - About phone a few times until you are being declared a developer.

Then disable Settings - System - Advanced - Developer options - Mobile data always active.
The description of this switch is “Always keep mobile data active, even when Wi-Fi is active (for fast network switching)”.

Sounds promising to me, but please report whether it helps with your networking issue, I just used it to work around a battery drain.


Thanks very much @AnotherElk – I never saw that switch. Seems bizarre to me that it was on by default!

Well, it’s “for fast network switching” (Who wouldn’t want that?) and doesn’t seem to do much harm in general.

Those with limit on their data consumption, and / or in my case money consumption.

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I just concluded from the positively worded technical feature why the switch is on by default :wink: .

And the mobile network being kept active for faster switching doesn’t automatically mean it’s being used on every device for significant data consumption while Wi-Fi is on.
Perhaps you could now run some tests on your device?


I guess it’s also relevant for power consumption. Switched this off now on my FP3. I have such a network change normally four times a day and it never came into my interest how fast this could be.

Thanks for showing me this option. I turned it off, but unfortunately I need to wait for 8 more days to receive new data from my provider. So for now I have no way of knowing if it works.

I will continue to monitor the tally at Settings > Network and Internet > Mobile network most days. I am now very optimistic that I will get less nasty surprises!

I ask my brain now if my problem of sometimes corrupted data connections (unsolved since 0.18) is also related to this …

I will still confirm that.

Holding a connection permanently open means technically to send a short keep-alive request every few minutes. In case of a mobile connection this can indeed cost a lot of energy depending on the distance to the next antenna. And if there are bad conditions or disturbances the request will even be repeated.

Normally my device used about 50% per day before I switched this permanent mobile connection off. It’s now about 28h since I completed the last full charging and I still have 70%.


You didn’t mention your device.
I am using FP3+ and - without Orbot active (drains a lot in v1.2) - the phone uses less than 1% an hour, resulting in some six days available usage.

I’m using an FP3 with the new camera module built in.

Exactly predictions are complicated because of different network use (mobile, wifi), different local conditions and different personal behavior. Everybody can check this on it’s own. In my case (which is characterized by only 1h per day on mobile connections, 15h on wifi and completely off over night) it gives me a lot to have mobile connections really switched off. And I never detected a change in behavior, when I lose wifi it reconnects to mobile immediatly within seconds.

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I was reminded of this thread by your comment Feedback for v1.5 - #229 by irrlicht.

My use of mobile data has been absolutely predictable since making this change, but more importantly so has use of my home and other networks ! It is speculation, but my experience fits with a situation where I expect to connect to WiFi network but mobile data is on; maybe WiFi does not come up instantly, so the connection is made by mobile data. Further speculation, this unpredictability seems to cause the WiFi network to lose interest in the connection … perhaps ?

I wonder if you continued with this setting off and if you consider this change to be any part of the improvement you report ?

I still have this off since then. And I never had bigger or unpredictable amounts of mobile traffic. I watch on that very carefully. Glasswire reports me a mobile “background noise” traffic of mostly about 350kB incoming and 150kB outgoing per day, not more, the biggest part comes from my mail app sending keep alives to the IMAP servers.

That a device prefers mobile over wifi connection could be a consequence of a bad or disturbed wifi environment. Most wifi routers allow a diagnose of the environment, you see then other networks on the same channels and can configure your own to use another one.