Yes, they can, but not always they do. And you can just switch to a new card then.

I see, good to know.

But still, while roaming was mandated to be free and easy within the EU, the carriers were allowed to have a limit to their "leniency", like 180 days, after which they could disable a SIM as having permanently moved to another country, and not simply roaming? Or is that outdated info on my part too? I can't find the details.

0xIlmari

https://www.patrick-breyer.de/en/no-right-to-anonymous-communications-european-court-of-human-rights-rubber-stamps-mandatory-sim-card-registration-laws/

Still available in some countries. And roaming is free within EU. So you can buy card in, let's say, Latvia, and then use in other EU country.

kristapsk

privacy

How to privately/anonymously use Telegram?

Signal312

You can still have anon SIMs up there? I was under the impression that "burners" were banned throughout the EU (because terrorists, oh my). 

Sure, you can buy a SIM preloaded with credits in a grocery store, but where I live, they require a subsequent KYC activation through the carrier's website. 