The cost of sending a text, making and receiving calls and using data is capped in the EU, but many holidaymakers aren't sure which countries are in the European Union, which could leave them facing hefty mobile phone bills.

Research from comparison site uSwitch has revealed that 48% of people incorrectly think Croatia – a popular holiday destination – is part of the EU, although it's set to join it on 1 July. Meanwhile 30% wrongly reckon Turkey is also an EU country (see our Cheap Data Roaming guide for help on preventing bill shock).

Norway, Switzerland and Iceland also throw people, with 45%, 36% and 32% respectively wrongly believing these countries are in the EU (check if your destination is in the EU on the European Union website).

But this confusion could result in many being hit with mobile bill shock when returning home, as holidaymakers using their phone in non-EU countries aren't protected by price caps.

uSwitch says Brits flying to Turkey for seven days this summer for example could run up a bill of £281 for making and receiving two five-minute calls, listening to a two-minute voicemail message, and sending five text messages and two photo messages each day.

While holidaymakers in Turkey using just 1MB of internet data, which uSwitch says is enough to view a few web pages and update your status on a social network, costs an average of £4.75 across the five major mobile phone networks.

But despite uSwitch finding that almost nine in ten (86%) people think roaming charges are too high, almost six in ten (59%) admit they won't check roaming costs before they jet off this summer, 44% plan to keep their phones switched on and not limit their usage, while almost a fifth (17%) fail to switch off data roaming in their mobile settings when overseas.

What are the EU price caps?

The price limits that now apply on roaming charges in the EU are:

  • Data: Capped at €0.70 per MB, changing to €0.45 from 1 July.
  • Outgoing calls: Capped at €0.29 per minute, changing to €0.24 from 1 July.
  • Incoming calls: Capped at €0.08, changing to €0.07 from 1 July.
  • Texts: Capped at €0.09, changing to €0.08 from 1 July.

The only measure that will help those travelling outside the EU is that all mobile operators have to apply a cut-off limit once you have used €50 (excluding VAT) of data per month, wherever you travel in the world unless you choose to opt out.

You will be warned via email or text if you're nearing the limit. The price of using data will however vary depending on which country you are in.

Avoid bill shock

Before leaving for your holiday you can do a few simple things to avoid getting hit with a big bill, such as switching off your 3G and using free wi-fi while you're away.

Many apps and programs, as well as the operating systems themselves, routinely check for available updates and download them automatically. So be sure to turn these off.

It's also best not to watch TV and films or download music and attachments.

For help on cutting data roaming costs, including the best data roaming add-ons, see our Cheap Data Roaming guide.