OnePlus
Show or Hide Caller ID auf OnePlus
By default, your OnePlus sends your caller ID based on your carrier's network settings. That means anyone you call typically sees your number unless you change this manually on the device itself.
The setting lives inside the calling accounts of the Phone app, not in the general system settings, which is why many users never find it. On a Dual SIM device, this value is stored per SIM card, so switching cards resets the behavior back to whatever that specific card was last configured to do.
To check or change it, open Open the Phone app ➔ Open the menu ➔ Open the Settings ➔ Tap on Calling accounts ➔ Choose a SIM card (Dual SIM) ➔ Tap on Additional settings ➔ Tap on Caller ID. From there you can pick Network default, Hide number, or Show number.
Network default leaves the decision to your carrier, which is usually to show your number. Hide number blocks your caller ID on every outgoing call from that SIM, which is useful for one-off private calls but can cause some recipients to reject unknown numbers automatically. Show number forces your number to display even if your carrier plan would otherwise hide it.
If you use two SIM cards, repeat these steps for the second SIM separately, since the setting does not carry over between them.