Martin Lewis explains how to avoid holiday roaming charges as 14 million 'massively overpaying'

Millions of holidaymakers could be paying too much on their phone bills while travelling abroad.

Some of the UK's biggest phone networks, including Vodafone, Three, and EE, all now charge around £2 a day for people to use their phone and data in the EU. In fact, the only large network that provides free roaming is Virgin Media O2.

In its latest newsletter, Money Saving Expert (MSE) stressed that roughly 14 million people are currently paying outside of their phone contract. Because of this, they have free rein to switch their provider and get a cheaper deal and free roaming in the process.

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Explaining how to 'beat' the charges, the newsletter said: "Vodafone, Three and EE all now charge £2ish/day to use your phone & data package in the EU. Virgin Media O2 is the only 'big four' network to still be free. Yet many piggyback operators are free to EU-roam too, including Lebara, Smarty and Giffgaff. Yet 14m of you are out of contract, free to switch and often already massively overpaying. So why not ditch and switch to save in the UK and when in the EU?"

If you're someone who doesn't need a lot of data, Lebara can provide a sim with 5GB for only £3.25 a month. For just a little more cash, you can get a sim on TalkMobile which provides 40GB a month for £5.45 a month or iD Mobile which provides 100GB for £7.50 a month.

If you travelling outside of the EU and you're someone who likes to really use their data for a wide variety of things while abroad, such as watching TV, it may be a good idea to invest in an eSim. These virtual sim cards provide you with a data allowance in another country for a much cheaper price than if you were using the ad-ons on your current. In some cases, providers can charge around £8 a day if you use your plan to watch TV outside of the EU.

Speaking on the latest episode of his podcast, MSE founder Martin Lewis dished out some advice to a caller who asked him how she could save money on using her phone abroad this summer.

Martin said one option would be buying a local e-sim, which could get you access to data while you're on holiday for around a tenner. But when it comes to avoiding the £2 a day charge, Martin said the best option was switching to a cheaper provider.

Unfortunately the caller was still locked into her contract with Sky, so that wasn't an option for her. But Martin advised others: "The big three and a few others - Vodafone, Three and EE - all now charge about £2 a day (ish) to use your phone and data package in the EU. Virgin Media O2 is the only one of the big four that doesn't. But loads of the piggy back networks that use the same signals as those big four (because they're the only signals available, they're the only actual networks all the others are virtual networks) give you free roaming and are much cheaper."

"Anyone out of contract in your situation should probably look at ditching their existing sim and going somewhere cheaper," he said.