Using your phone abroad can be expensive — but with a little planning, it's easy to save a lot of money.

If you're unprepared, using your phone overseas can add hundreds of pounds to the cost of a trip abroad, in the form of an enormous roaming bill when you return home. Fortunately, international roaming is more affordable than ever. Depending on your network and circumstances, it's easy to keep costs to a minimum. And even if your phone is locked to a network with unfriendly roaming rates, you've still got plenty of options.

Let's dive in.

Check roaming bundles before you travel

Roaming fees can vary wildly depending on which network you're on and where you're going. It can make the difference between being able to use your phone freely as if you were at home, or any data use being prohibitively expensive.

A few things worth noting:

  • Vodafone contract customers will want to check if they're enrolled in EuroTraveller or WorldTraveller. The former lets you use your UK allowance — including tethering and 4G where available — for £3 per day in certain European countries. The latter lets you do the same in certain countries outside of Europe, for £5 per day. Both could save you a lot of money if you're a heavy data user.
  • Three customers should check if their destination is part of the network's "Feel at Home" area, which allows customers to use their UK allowances in certain territories at no additional cost — with a few strings attached.
  • If you're an EE grandfathered into the carrier's "special rate" for roaming, you may get a better deal than the rates displayed on EE's roaming site. Double-check with the network to make sure.

Disable roaming data entirely and use Wi-Fi

This is the sledgehammer option — completely kill data roaming and only connect to Wi-Fi hotspots while you travel. On Windows 10 Mobile, you'll find the roaming option under Network and wireless > Cellular and SIM. Select your network, then tap "Properties."

There are a few obvious places where you might find free Wi-Fi — hotels, coffee shops, airports, train stations and the like.

Disable background data for certain apps

Switching off background data will stop apps using cellular data when they're not open. Check out our guide to disabling background apps for more information.

It's also easy to monitor data usage on your Windows 10 devices to avoid chewing through your roaming allowance.

Unlocked phone? Use a local SIM card

If your phone isn't locked to your network, you can simply pick up a local SIM card from a carrier in your destination country after you arrive. These are often available from airports or convenience stores — and, naturally, from local carrier stores. While this can be a great option if you want to save money on mobile data, bear in mind that you might not be able to make international calls back to the UK from a pre-paid local SIM.

Services like HolidayPhone let you order a prepaid SIM for your destination country before you travel, taking some of the uncertainty out of tracking down a local SIM while abroad. You'll usually pay a little more for a service like this, however.

SIM-locked phone? See about unlocking

Even if your phone is locked, you could still save money by getting an unlock code before you travel. In many cases, even with the upfront cost of unlocking your phone, you could save money in the long run by using a local SIM abroad.

  • All phones sold on Three from the start of 2014 are SIM-unlocked. For older devices, you can use this form.
  • O2 will normally unlock contract customers' phones for free, with a few exceptions. For PAYG customers there's a £15 charge.
  • EE will unlock devices if you've had your contract for six months or more, or immediately if you're on PAYG. Unlocking costs £8.99.
  • Vodafone will unlock phones for free if you've been on contract for 12 months or more. If you've had your contract for less than 12 months, or you're on PAYG, it costs £19.99.

How do you manage roaming costs while abroad? Share your tips and tricks down in the comments!