Can police search my phone after an arrest?

Arrest permits seizure of the phone. It doesn't, on its own, permit examining what's on it.

Officers may secure the device — including powering it down or placing it in a bag that blocks signal — to prevent remote wiping while a warrant is obtained. That's preservation rather than search.

Where people lose this protection is by consenting. A request to "just take a quick look" at the moment of arrest is a request for consent, and it can be declined. So can a request to open the phone to show something specific, which frequently becomes broader than intended.

Two related points. What you say on a recorded jail call about your phone's contents can matter. And a phone belonging to someone else, or a shared device, raises separate questions about who could consent to its search.

If your phone was searched, the questions are whether there was a warrant, what it authorized, and whether the search stayed within it.