Roaming in the EU--any extra charges for non-EU citizens?

Do you have a link to these reports of extra roaming fees? I've not heard of them.

I got my Dutch Vodafone SIM last spring (they voluntarily dropped roaming fees on their plans a few months before the EU rules went into effect) and I certainly didn't pay anything extra to roam - in fact, I never used it in the Netherlands, only in Slovenia, Italy, and France. Last used in May.

https://community.ricksteves.com/travel-forum/tech-tips/dutch-vodafone-sim-card-for-use-in-europe

Here's what I found on one site:

Theoretically, then, if you’re not an EU resident, mobile companies aren’t obligated to offer you “roam like at home” pricing. That’s potentially bad news for visitors from elsewhere in the world, who plan to buy a SIM card in the first EU country they visit, then use it across the continent.

Practically, though, many carriers are unlikely to bother trying to restrict their service like this. I spoke to a customer service representative for EE, the largest mobile company in the UK, who confirmed international visitors will be treated the same as any other prepaid customer. As long as they abide by the standard fair use policy, they can roam across the EU like anybody else.

My advice for international tourists planning to use a SIM in this way, though, is to ask this specific question before purchase. Each operator is different, and especially in cheaper Eurozone countries, some may look to keep their costs down by enforcing this part of the regulations.

See https://toomanyadapters.com/no-eu-roaming-charges-travelers/

I've basically heard the same thing but I read it differently. These mobile companies may crack down on people who use these SIMs EXCLUSIVELY for roaming - e.g. you buy a UK SIM card and use it mostly or entirely outside the UK. And I understand it to mean that you'd have to do it for a while - like an ex-pat who is living in say France but is using a cheap UK SIM to roam there for months at a time, not a tourist visiting for 2-3 weeks and using the SIM outside the OK.

Further, some of them don't even know your nationality. When I signed up for an account on the Dutch Vodafone website after buying and activating my SIM, I did not provide them an address. (Many countries require you to register with your passport, but some like the Netherlands do not.) They can tell where I've used the SIM of course (not in the Netherlands so far!), so they could in theory shut me off at some point if I don't start using it in the Netherlands sometimes. But I'm not overly worried about this happening.

The major concern are not tourists but people reselling GSM cards from cheaper countries online for those using it long term exclusively elsewhere. Think a resident in Germany using a much cheaper Bulgarian GSM all the time while not living in Bulgaria...

Thanks for clarifying. Four months seems to be the trigger. I found this explanation in the article I cited earlier:

"The basic rule is that, over a four month period, you’re covered by the new regulations as long as you’re spending more than half your time in your “home” country, or more than half your phone usage is in that country. If not, your carrier can contact you, then start charging the overage rates. If you’re on a tourist visa, and can’t stay in the EU that long anyway, this is unlikely to affect you, but it’s worth noting."

If anyone has roamed for more than four months and been penalized, please share your experiences with us.