Uh, don't you need an Apple ID to activate an iPhone?

Nope, you can just click skip. If the device had previously been enrolled in Find My iPhone you have to log back in to turn it off, but if it’s fresh out of the box you don’t have to hook it to iCloud/iTunes at all (and that’s not uncommon to block in corporate environments).

Not on my end, no skip button.

Not sure what device you’re on but every iphone I’ve set up I’ve (at least initially) skipped signing in. It’s not hidden or subtle or anything (especially compared to latest windows OS), it’s a big Skip link. The main downside is you can’t install any apps, and in my experience iMessage does NOT work until you log in with apple ID, just SMS/MMS.

Could be country specific..

True, or carrier lock specific if it involves activation. I would be surprised by this though, and deeply dislike the idea.

Phone still works without an ID. No idea if this means that you can only send SMS messages though.

I’m not logged in I can send iMessages and FaceTime, seems to link it to the phone number though.

It does.

The question was about phone numbers, not apple id.

You need a phone number for Apple ID, don't you?

Using iMessage requires an Apple ID. The Messages app on iPhones supports both SMS/MMS and iMessage because it’s a phone and needs to support SMS. But without being signed into an Apple ID on the device the Messages app only handles SMS/MMS, i.e., green chat bubbles.

That isn't true. You can use iMessage without an Apple ID on a phone. It uses your phone number. I promise you of this.

Yes, but if you don't have an Apple ID, the iMessage app will use SMS/MMS, not the proprietary encrypted Apple messaging protocol. This can be tested easily: send a message to another Apple user: it will arrive as a green SMS message, not a blue Apple messaging message.

iMessage without an appleid is just SMS…

> You don't need an Apple ID to use iMessage. Just an Apple device.

Has Apple fixed the bug where it wasn't relinquishing your phone number and blackholing all iMessages which were supposed to be downgraded to SMS instead?

Years ago, yes: https://selfsolve.apple.com/deregister-imessage/