Millions are being treated to a holiday travel perk from Sky.

The provider is rolling out a free upgrade to its mobile service that lets you use your phone worldwide without paying a penny in roaming charges.

It's reserved for Sky VIP Diamond members — that's anyone who's been a Sky customer for more than 15 years. That includes Sky broadband and its satellite television subscription. Whether you're already on Sky Mobile or just signing up, the perk kicks in as long as you hold that Diamond status.

The free roaming covers a whopping 120 destinations worldwide. This includes popular spots like the US, Australia, South Africa, India and Thailand.

If you're heading overseas in the coming weeks, this could save a decent chunk of money on those dreaded roaming bills.

For comparison, rival networks like EE and Vodafone currently charge as little as £6 a day to use your phone outside the UK — that's for data and calls. So if you're away for a fortnight, you could easily be paying an additional £84.

Although if you have mobile plans with O2, iD Mobile, Smarty or other providers, there are other ways to get roaming for free.

Switch to Sky and get 50GB of data for half price

For the first six months of your mobile plan, you can get 50GB of data for only £10 per month. You can change your data plan whenever you like and roll over any extra data to the next month. Plus, you can roam in over 120 destinations for just £2 per day.

These mobile providers – alongside several others — offer EU roaming at no extra cost in your plan. That means you could hop over to Italy or France and not have to pay anything extra to stay connected.

Before Brexit, EU law guaranteed free roaming and set automatic protections, like mandatory spending caps such as £45 per month and usage alerts.

Since Brexit, the EU's "Roam Like at Home" guarantee no longer applies to UK mobile users — meaning UK networks are free to set their own terms. This has led other major networks like EE, Vodafone, and Three to reintroduce daily roaming fees.

If you don't hold Diamond status at Sky, then you'll be subject to a £2 fee per day when you travel throughout Europe.

Here's a full breakdown of the mobile providers who either offer EU roaming for free or at a daily cost.