Calling Spain, Poland etc from your UK mobile? Weirdly it's cheaper outside the UK

New EU rules will abolish roaming charges for many, slashing the cost of using your phone in Europe. But a curious quirk remains – it's cheaper to call other EU countries on your UK mobile once you're abroad, rather than do it from the UK.

There's been some confusion over what calls from EU countries will cost under the new rules, with some MoneySavers claiming they've been given wrong info by their networks. Yet we've had the anomaly confirmed by the European Commission and eight major UK mobile firms.

For full info on how the new rules will work, see our 10 'free' EU roaming need-to-knows.

It's cheaper to call an EU number while roaming than from the UK

The European Commission today launched its 'Roam Like At Home' rules which mean you'll be able to call most landlines and mobiles within the EU for the same price you'd pay if you were in the UK calling a UK number.

So if you've a monthly allowance it'll come out of your minutes – if you've got pay-as-you-go (PAYG) credit, you'll be charged your usual UK rates. If you go over your allowance or bundle you'll be charged your network's UK rates.

However, calls to EU countries from your UK mobile, while you're in the UK, aren't considered 'roaming' and will be charged by your network as an international phone call.

So, for example, if you're in Spain and make a call to a local Spanish number on your UK mobile, it will be cheaper than calling the same number from the UK. What's more, when in Spain it'll be cheaper to call anywhere else in the EU than if you made those same calls in the UK.

It's even cheaper to call the UK from Spain than calling Spain from the UK. And of course, what works in Spain works in all other EU countries (except the UK, assuming you're using a UK mobile).

Martin: 'In many ways new rules are counter-logical'

MoneySavingExpert.com founder Martin Lewis says: "There's a lot of confusion over the new roaming rules and what calls are included and aren't. This isn't surprising as in many ways they're counter-logical.

"After all, it's a bit bizarre that if you call to book a Spanish restaurant on your UK mobile from home before you jet off, you'll pay a whopping international call cost, but save making the booking call until you arrive in Spain and it'd count as part of your free minutes.

"And it's even more bizarre that if you call your grandma in Poland on your UK mobile while in Spain, that's part of your free minutes too. Yet if you call her from the UK to tell her you've arrived back home safely, you'll likely pay expensive international call costs again. In fact, if you have lots of EU calls to make, it's cheaper to wait until you're abroad to do it."

How do call costs from a UK mobile compare?

To highlight the discrepancy, here's a comparison of calls (we've used the UK, Spain and Poland but it would apply to any EU countries):

Calls to EU countries from your UK mobile

Here are some of the major networks' standard charges for international calls to the EU from the UK:

• EE – 30p/min PAYG, 50p/min on contract

• O2 – £1.50/min on contract and PAYG

• Three – 46p/min on contract and PAYG

• Vodafone – £1/min PAYG, £1.50/min on contract

A few EU numbers, such as premium rate lines, could still cost more when called from the EU, even if there's no extra roaming charge – so if unsure, check with your network first.

Although the new EU rules come into effect today, a similar anomaly has existed for the past few years and we've long warned about it – in 2014 our Mobile Roaming Report called for mobile networks to reduce UK domestic costs to reflect previous EU changes.

The European Commission launched its 'Roam Like At Home' rules today

Some could still face extra charges for using their full UK data allowance

The anomaly over call charges isn't the only thing to watch out for in the new regulations.

As MoneySavingExpert revealed last month, the 'fair use' small print of the EU rules means some users on cheaper mobile deals could be charged extra fees to use their full UK data allowance. (There are no extra charges for calls or texts.)

The exact amount of your data allowance you can use before these extra charges kick in varies by provider, and can depend if you're on pay monthly or PAYG.

See Extra data charges for a full list of providers' limits and extra charges and our 10 things you need to know about EU roaming for more to watch out for, including a warning that the new rules may not apply onboard ferries or cruise ships.