Apple Watch 10 cellular function affected by BT?

[herbert7265]

All

Maybe, maybe not somebody can help me with a weird problem I face with my Apple Watch 10 regarding its cellular functionality.

First of all, I am using
- an Apple Watch 10, GPS+Cellular, watchOS Version 26.1 with
- an Apple iPhone 16 Pro, iOS Version 26.1

Problem description:

- I was using my AW 10, together with the iPhone 16 Pro, since around October 2024, without any problems. Before I used an older AW, with an older iPhone, also without any problems. All my Apple Watches have (had) the cellular functionality and I have contracted the service via my cellphone carrier Telcel (I am living in Mexico).
- My wife also is using an AW 10, with GPS +Cellular, but with an iPhone 14 Pro Max.
- A few weeks ago I observed the first time that my AW showed in the Cellular function / screen the status "No Connection", despite showing my cellular plan. Checking the plans for my cellphone and my AW everything was active and normal.
- When I first observed the problem my iPhone and my AW had still not been updated to iOS / watch OS 26.
- Interestingly, when I detected the problem on my AW I also detected the same problem on the AW of my wife!

To make a long story short, after I detected the problem the first time I was several times in contact with the technical support of my cellphone and watch service carrier, but with no real success. My first assumption was that this is a problem of the carrier, considering it appeared on different devices, different OS and so on. But what ever they did, it solved the problem for a few days, then the same problem appeared again with my AW, but also with the one of my wife.

Today now I made an interesting observation:

Since three days the same problem again, means neither my AW, nor the AW of my wife, connected to the cellular service, after it worked for approx. 2 weeks (after my last contact with the support of the carrier).
Being a little annoyed, I simply tried different things today with my AW to see if I may find at least a hint what is going on, without again spending time with the support of the carrier. And here we go...!

When I
- turn off Bluetooth on my iPhone
- then restart my iPhone (with BT turned off!) and my AW (not changing the BT setting on my AW!)
- the my AW connects to the cellular service after the restart and everything works!

But
- as soon as I turn on Bluetooth on my iPhone again
- the cellular service on my AW stops working again, shows again "No Connection"
- does not connect again, even I turn off BT again on my iPhone, go into "Airplane" mode on each of the devices, etc.
- and only works again when I again turn off BT on my iPhone and restart both devices.

Has anybody any idea what could cause this weird behavior and, hopefully, how it could be solved?

No, I have not decoupled and re-installed my AW from my iPhone today, but I did that when the problem appeared the first time, with no success (but I can do it again, no problem).

No, I could not check the AW of my wife at this moment, as I am at work, but I will do so in the evening. And I am quite confident it will show the same behavior.

Herbert

 

[Howard2k]

The watch prioritizes the radios:

1) Bluetooth connection to phone - least expensive on power.
2) Wifi connection - second least expensive on power.
3) Cellular - will activate if there is no BT nor Wifi to connect to.

So yes, while BT has an active connection, or while Wifi has an active connection, the cellular should not be in use.

You need to ensure that there is no BT and no Wifi available to the Watch, and then give it a few minutes to connect to the Cellular network.

 

[herbert7265]

@Howard2k

The watch prioritizes the radios:

1) Bluetooth connection to phone - least expensive on power.
2) Wifi connection - second least expensive on power.
3) Cellular - will activate if there is no BT nor Wifi to connect to.

So yes, while BT has an active connection, or while Wifi has an active connection, the cellular should not be in use.

You need to ensure that there is no BT and no Wifi available to the Watch, and then give it a few minutes to connect to the Cellular network.

Okay, it seems to work as you describe, with only one, but fundamental, exception (at least in my case): The AW does not connect any more to the cellular carrier on its own, I need to restart it that it (re)connects!

Any idea what can cause this issue and how to resolve it? And again, in the past I didn't see that behavior, only since a few weeks!

Herbert

 

[Howard2k]

@Howard2k


Okay, it seems to work as you describe, with only one, but fundamental, exception (at least in my case): The AW does not connect any more to the cellular carrier on its own, I need to restart it that it (re)connects!

Any idea what can cause this issue and how to resolve it? And again, in the past I didn't see that behavior, only since a few weeks!

Herbert

It should take a minute or two. To be sure, please disable the BT and Wifi radios on the Watch (not the phone) so that only the cellular radio on the watch is active. Does it connect then?

(In other words, you need to ensure that the Watch is not connecting to Wifi, turning off Wifi on the Watch is the sure way to do this).

 

[jetsam]

The watch prioritizes the radios:

1) Bluetooth connection to phone - least expensive on power.
2) Wifi connection - second least expensive on power.
3) Cellular - will activate if there is no BT nor Wifi to connect to.

So yes, while BT has an active connection, or while Wifi has an active connection, the cellular should not be in use.

You need to ensure that there is no BT and no Wifi available to the Watch, and then give it a few minutes to connect to the Cellular network.

Your hierarchy description is correct - but the OP should still see "Connected" under the plan name on the watch.

I have a 16 PM and an AWU2, both on 26.1, and a cellular plan with AT&T. And even though my watch is attached to the phone via BT, I still see the word "Connected" under "AT&T" on the Cellular page on my watch.

 

[Howard2k]

Your hierarchy description is correct - but the OP should still see "Connected" under the plan name on the watch.

I have a 16 PM and an AWU2, both on 26.1, and a cellular plan with AT&T. And even though my watch is attached to the phone via BT, I still see the word "Connected" under "AT&T" on the Cellular page on my watch.

That is true. I just checked and I see that too (Connected under Status).

 

[wilderkun]

You’ll shouldn’t need the cellular when it’s in range of Bluetooth from your phone. The cellular will come on automatically when your out of Bluetooth range

 

[herbert7265]

Your hierarchy description is correct - but the OP should still see "Connected" under the plan name on the watch.

I have a 16 PM and an AWU2, both on 26.1, and a cellular plan with AT&T. And even though my watch is attached to the phone via BT, I still see the word "Connected" under "AT&T" on the Cellular page on my watch.

That is true. I just checked and I see that too (Connected under Status).

That's exactly what I observed in the past, before the actual problem showed up!

You’ll shouldn’t need the cellular when it’s in range of Bluetooth from your phone. The cellular will come on automatically when your out of Bluetooth range

Nope, that's exactly what is not happening, as already described above!

Herbert

 

[herbert7265]

It should take a minute or two. To be sure, please disable the BT and Wifi radios on the Watch (not the phone) so that only the cellular radio on the watch is active. Does it connect then?

(In other words, you need to ensure that the Watch is not connecting to Wifi, turning off Wifi on the Watch is the sure way to do this).

I did that and it does not work! The only way to get the cellular service connected is to restart the watch!

Herbert

 

[teh_hunterer]

I did that and it does not work! The only way to get the cellular service connected is to restart the watch!

Herbert

Are you sure it's not just a bug that it doesn't say it's connected? Have you tried making a phone call from it to see if it might actually be connected but isn't saying so?

 

[herbert7265]

Are you sure it's not just a bug that it doesn't say it's connected? Have you tried making a phone call from it to see if it might actually be connected but isn't saying so?

Yes, I tried that one (cell phone switched off, BT and WiFi turned off on the AW), but I can neither receive nor make calls when it shows "No connection"!

On the other side, when the cell phone is off, BT and WiFi are off on the AW, and it shows connected after the restart, I can make and receive calls.

Herbert

 

[herbert7265]

Okay, after some more investigations, trials and whatever else the situation looks now as follows:

- The issue is not related to my cell service for the AW!
- The issue is (seems to be) related to something that involves at least the BT and the cell service (in combination) on my AW!

REMARK: The service of Apple Care also couldn't help my by phone. Most likely I have to bring / send in my AW physically for service, what is not that easy here in Mexico (no Apple stores around!).

Situation description:

After completely setting up my AW, as the recommendation of Apple Service by phone, as a new device the functionality (cell service connection) worked again for a few days and then stopped again! Then the situation was / is as in the past: The AW is connected to my cell phone via BT, but the cell service shows no connection, despite showing my cell service plan. When I then get out of reach from my cell phone I have no more connectivity functionality at all, as BT is no longer connected to my cell phone and the cell service is, as stated, not connected.

The interesting thing: When I then turn off and on my AW, still out of reach from my cell phone (or have BT off on my cell phone), then my AW connects normally to the cell service with full functionality. But as soon as I get again into reach of my cell phone, or turn on BT on my cell phone, the cell service ob my AW disconnects again (until the next restart as described).

I am not talking about WiFi, as it is the same situation!

Has anybody any idea what can cause this curious issue?

An interesting additional aspect: I face this issue on my AW10, my wife also on her AW10. But our daughter does not face this issue on her AW11.

Thankful for any idea or hint!

Herbert

 

[Mind The Mac]

Have read your posts/updates and clearly some "event" on you/your wife's devices has occurred - OS update/Sim or e-sim change/historic device upgrade/home wifi/TelCel account in the past. I am sure you have thought long about that, but it's odd that you both suffer this issue especially if your daughter is on the same account and all is OK on those devices. But it could still be how your devices are provisioned by TelCel.

Some thoughts:

Have you compared your daughter's iPhone sim settings - APN etc?

During your sessions with TelCel/Apple Support did they have you reset your phone's Network Settings? If not this might be worth trying. Note it will clear all wifi/bluetooth connections also, so you'll need to re-pair/establish those connections (check Apple's site about if you need to unpair the watch first), but it will remove any potential corrupt settings and as the watch gets it connectivity settings from the phone, this might clear an issue. My thinking is the phone is not "releasing" the watch to the TelCel network, so you cannot connect outside until you "break" the connection by restarting, which from your comments then enables normal service.

If you have done this already, then excuse me repeating other's guidance.

Edit: note about "Check Apple's site....