How do you disable background reading?
Neither platform offers a switch for background reading specifically. Switching NFC off entirely is the only complete answer on Android, and on an iPhone there is no separate control at all, which surprises people who go looking for one in the settings.
On Android
There is no preference that keeps NFC available while preventing the system acting on tags. Acting on a tag is what the dispatch system is for rather than an option within it.
So the complete answer is the NFC toggle itself, which is available in the settings and usually in the quick panel.
The partial answer is an application in the foreground claiming tags, which stops the system acting for as long as that application is on screen.
A narrower one exists from Android 16: the first time an app receives a tag, a notification lets the user stop that app receiving tags, and the NFC basics guide places the list under Settings > Apps > Special app access > Launch via NFC. From Android 17, a tag holding a web link no longer opens until the user acts on a notification.
They are covered in more detail in the guide on stopping Android opening tags automatically.
On iPhone
There is no NFC toggle and no background reading control. The capability is present on supported models and managed by the system.
Background reading is available from the iPhone XS and XR onwards, and where it is available it is not something the user switches off.
Take NFC Tools. On iOS it requires an iPhone 7 or later running iOS 15.6 or later, and the app must be launched manually. Background reading is available from the iPhone XS and XR onwards.
What does exist is the confirmation step. A background read produces a notification, and ignoring it means nothing further happens, which is a form of control even if it is not a setting.
Partial measures
Move the tag rather than changing the phone. A tag being read repeatedly is usually a tag in a place where a phone is regularly put down.
Cover it with metal if it is fixed and unwanted. A metal surface against a tag cancels the field, which is the physical equivalent of switching it off.
Keep a written tag away from where a phone rests, particularly on a desk or in a bag with the phone.
And on a managed device, an administrator can restrict NFC centrally, which is the only route to enforcing this across a fleet.
Why people want this
Repeated triggering from a tag they own, which is a placement problem with a placement solution.
Caution about tags in public places, which is better served by opening a reading tool before tapping anything unfamiliar. That way you see what a tag holds instead of acting on it.
Battery, which is not a good reason. The cost of leaving NFC enabled is small.
And a general preference not to have the phone act on objects, which is legitimate and is served by the NFC toggle.
Frequently asked questions
Is there an iPhone setting for this?
No. There is no NFC toggle and no background reading control, since the capability is managed by the system.
Can I keep NFC on and stop tags acting?
Only while a foreground application claims them, on Android. The one persistent setting, from Android 16, stops a given app receiving tags rather than tags acting in general.
Will switching NFC off stop payment too?
Payment is reached through its own path and can behave independently, so test rather than assuming either way.
How do I stop one specific tag?
Move it, or put metal behind it. Both are more practical than changing how the phone behaves generally.