In Spain you must present a valid ID since a few years ago. After a grace period they deactivated all SIMs not linked to a name.

Italy still requires to link a SIM to a person. I don't remember if I had to show my id or my fiscal code last time I got a new SIM. No more than a 30 seconds procedure. They note it down and that's it. It's been like that for so long that I forgot when and why they introduced this legislation.

It is still required to have your name tied to SIMs in Italy. You are asked to show an ID (or driver's license) and your fiscal code[1].

[1]: https://en.wikipedia.org/wiki/Italian_fiscal_code_card

I had to show ID in Czech Republic, Hungaria, Ireland and Greece.

> Czech Republic

I have a czech prepaid sim, never had to show an ID for it.

> Hungaria

True, ID needed there.

> Ireland

I had an Irish Three Sim. No ID was needed.

> Greece

Looks like an ID is needed there from Googling.

I confirm: in Ireland you can buy a sim (I have a tesco mobile SIM) with no ID