Researchers in Ireland examined the amount of iOS and Android data sent to Apple and Google.
For example, Apple and Google get device IMEI, hardware serial number, SIM card serial number and IMSI, phone number, and other data. Moreover, Android and iOS continue to transmit telemetry to their manufacturing companies, even if the user does not specifically disclose this data. In fact, as soon as a user inserts a SIM card into any device, the corresponding data is transferred to the parent companies of each of them.
By the way, there is no way for users to avoid having iOS devices tell Apple the MAC addresses of nearby devices and GPS location data. Indeed, these users don’t even need to log in for the device to share data. On the other hand, Google collects much more data from nearby devices than Apple.
In comparison, Google gets about 1MB of data, compared to 42KB for Apple. On standby, Android Pixel sends about 1MB every 12 hours, while iOS sends 52KB. Google collects about 20 times more data from mobile phones than Apple.
Additional features like iCloud, Safari, and Siri send user data to Apple regardless of whether they allow it or even know that their data is being transferred. On Google Android, these apps are broadcast by Chrome, YouTube, Google Docs, Google Messaging, Clock, Safetyhub, and Google Searchbar. The main reason these devices end up sending so much data is connecting to an internal server that is automatically updated by IP address. Once a company has an IP address, it can usually determine the corresponding geographic location.