That's not true in general. UK phone companies love to charge astronomical international rates when they can get away with it. Only EU maximum charge limits have capped these.

For example, in an EU country like Greece, I can phone a UK number for a maximum of 18p/minute. If I happen to travel near the border with Turkey and connect via one of their networks, there's no regulatory maximum price and the cost jumps to 69p.

It doesn't matter about it being true in general - the fact that any UK networks allow you to have unlimited data in America for no extra cost on a contract that is much much cheaper than US contracts shows that the US carriers are screwing you - I pay £15 a month (no contract - I can stop whenever I want) and that includes unlimited data in America.

What you're saying though is still not true:

I can go to US and use unlimited data for no extra charge.

There is a charge; it's part of your contract package. I'm sure it's a fantastic deal and for a traveler who uses mobile data in the US, it makes a lot of sense. But Three aren't doing this out of the goodness of their hearts. The charge for this data is part of your phone plan. Three (or another network) could provide an alternate package that didn't provide 'free' US data for a lower monthly cost.

You don't get it, the cost of my contract is much much cheaper (we are talking 25% of the price) than any unlimited US contract and yet it includes the same stuff.

No, it doesn't. Not knowing much about the UK market, I don't really have enough information to base an opinion on.

My first wild guess would again be regulatory: do they have to eat the extra costs involved so they provide you with the same price every month?

I'm pretty sure the regulatory thing is actually not even true. The article author was probably thinking of broadband.

Probably the real reason for the lower price is that all networks have pretty similar coverage, so the only thing to pick between them is price. Maybe there is also the fact that PAYG was very popular here in the past, so consumers just expect lower prices. Oh, and we don't have to pay the subsidy-tax for unlocked phones.

>My first wild guess would again be regulatory: do they have to eat the extra costs involved so they provide you with the same price every month?

Nope, only one network does it (the same network in the article) and it is one of their many great features.

As cstross mentions in another comment talking about Three it seems to be part of a big "Fell at Home" marketing campaign. With no other obligation to do so, I would simply assume they saw it as a good opportunity to stand out in a crowded market.

The all-you-can-eat nature seems to include voice as well as data abroad, but I haven't seen any mention of international calling. Calling another UK number I'm sure works as normal, but presumably you still pay the regular rates if you call a US number? They certainly do if they call you. If you're just visiting the states for a week or two that's not nearly as big a deal (use the free local calls from the hotel phone to order pizza), but longer trips (school or business) would still involve meeting a larger group of people and become cost-prohibitive (for both parties).

Combined with the limited number of customers who would be traveling internationally at all and likely the ability to get some sort of bulk-purchase agreement with whichever carrier in the US they use and they're probably just happy to eat the (relatively) limited expense to get the added customers.

Like I mentioned in another comment, it also plays heavily into our hatred of limits. If I want to skip off to NYC for the weekend, I don't want to have to figure out what to do about my phone first! The "don't worry about it, we've got you covered" approach is probably working out really, really well for them, even for the large majority of people who never travel... because they might, one day. In the meantime they keep paying every month.

Three offer unlimited roaming data in the US. They're not under any regulatory obligation to do so, and they presumably must be paying the network providers. I live in Canada right now, which is even worse than the US in this respect, and it is infinitely cheaper for me to use my British SIM in the US than it is for me to use my Canadian one. That's kind of nuts.