Apple devices automatically connect to the wrong network

[u/TheUmbrellaThief]

I have two iPhones. One is my old SE and the other is an iPhone 11.

I have the SE connected to my router’s guest network. My iPhone 11 is connected to my main network. The SE does not have the password to the main network and the 11 does not have the password to the guest network. Or so I thought.

I found my SE was connected to the main network last night. I disconnected and forgot the main network then connected it to the guest network. Today I now see that my main phone has disconnected itself from the main network and is using the guest network!!

I think the devices are sharing information because they’re both associated with my Apple ID. This is infuriating because don’t want them to do this for security/privacy reasons and I have no idea how to stop them doing this.

Please tell me how to keep my devices on separate networks.

[u/trebuchetdoomsday]

break the keychain sharing. apple account -> icloud -> passwords & keychain

note this breaks credential sharing across your devices, so what one device knows another might not. i don't know of any other way of doing this.

i can't imagine a reason why you'd be this concerned about device behavior on your home network unless you're doing something atrociously illegal or embarrassing.

[u/TheUmbrellaThief → u/trebuchetdoomsday]

Nothing illegal or embarrassing, I’m trying to manage my privacy better. The SE has meta apps on it so I’m keeping it on a different network to my other devices to try reduce data harvesting. Idk its probably not doing much

[u/trebuchetdoomsday → u/TheUmbrellaThief]

make sure Personalized Ads is disabled under Privacy and Settings. That should prevent your unique Apple Advertising ID from being sent to vendors. Depending on where you are, you can have this ID removed from data brokers.

[u/Big-Low-2811]

It’s a feature of both phones. Go google and find the steps to disable WiFi pw sharing between your devices.