Do foldable phones behave differently with NFC?
Yes, in one way that matters. The back is not a single surface, so the coil sits in one of two panels and the usable area changes depending on whether the phone is open or closed. Finding the spot is the same exercise done twice.
Two panels, one coil
A folding phone has its back divided, and the NFC coil lives in one part of it. Presenting the other part reads nothing.
That halves the effective target area compared with a conventional phone of similar size, and the owner has no indication which half is live.
People who have owned one for a while have learned it without noticing. People handed one for the first time have not.
Open and closed
Folding changes which surfaces face outward, so a coil that is exposed in one state can be facing inward in the other.
A phone tapped while closed and a phone tapped while open can therefore behave differently with the same tag, which is confusing until the cause is named.
Test both states when establishing the position, and note which one works.
For a deployment where staff use folding phones, that detail belongs in the instructions rather than in each person's memory.
The hinge and the metal
A hinge is a substantial metal structure running across the phone, and metal is what NFC coils cannot sit behind.
That constrains the coil position further than in a conventional phone, which already has little room.
It also means the region near the fold is the least likely place for the antenna, which narrows the search when you are looking for it.
What to do about it
Find the position in both states, with the case off, using a large tag and slow passes.
Note it against a visible feature so it can be described to someone else.
For public deployments, change nothing. A large tag with a printed target already accommodates an approximate approach, and that is what serves an unfamiliar phone of any shape.
And do not treat a folding phone as evidence about a tag. A tag that fails on one and works on a conventional phone is telling you about the phone.
Frequently asked questions
Does the hinge block NFC?
It is metal, so the coil cannot sit behind it. That constrains the position rather than blocking reading generally.
Should I tap it open or closed?
Test both, since folding changes which surfaces face outward. One state usually works better and it differs by design.
Are folding phones worse at NFC?
Not inherently. The usable area is smaller and harder to find, which makes them feel less reliable to someone who has not learned the spot.
Do I need different tags for them?
No. A large tag with a visible target serves them exactly as it serves any unfamiliar phone.