Making calls, sending texts and using the mobile internet while you're abroad can be costly.
Nowwhere is that more evident in the fact that so-called 'bill shocks' still regularly make headline news, with British holidaymakers stung by hefty charges they weren't aware they were racking up.
Fortunately, things are changing.
The European Union has voted to completely remove roaming charges by June 2017, meaning you'll pay no more than you would in the UK to use your smartphone, as long as you are in an EU country.
In the meantime, charges for phone use in EU nations are being reduced gradually.
From April 30th 2016, networks will only be able to charge five cents (about 3p) per minute for a call, two cents (just over a penny or so) for a text message and five cents (once again, about 3p) for a megabyte of data downloaded.
However, all networks have their own add-on packages for those going away either on holiday or business. These entitle you a set amount of calls, texts and data overseas for a one-off charge.
Find the right one for your needs and it'll hugely help you cut your outgoings on overseas phone usage.
Here we take a look at them in turn to see what's on offer and pick out the overseas phone usage bundles we think are the very best on the market.
Three’s ‘Feel At Home’ offer is by far and away the best deal for those looking to use their smartphone abroad.
There are 19 countries where you can use your at–home allowance of calls, texts and data without paying extra and without having to tell Three you’re going away.
These are in Europe and beyond. You can see the full list of countries here: Three Feel at Home.
Three claims that Feel at Home saves customers an average of £202 per trip.
Calling numbers within a country will cost extra. But you'll be notified of the rates by a text message from Three when you arrive at your holiday destination.
Just be aware that not all EU countries are included at this time.
To find out how much you could save, use the special calculator on Three's website.
Three also has a £5 per day Euro Internet Pass for other destinations.
Vodafone offers two key packages for using your phone or tablet abroad.
Its EuroTraveller deal allows you to make calls, send texts and access the web for £3 a day in 39 countries, although as with Three this only includes your UK allowance. Making local calls costs extra.
Its WorldTraveller package offers those heading away on long–haul trips the same deal, but for £5 a day.
This include 58 countries, which you can see in full at Vodafone's dedicated page.
However, it's worth noting that to use WorldTraveller you need to be a Pay Monthly or business user.
O2’s Pay Monthly customers can stump up £1.99 per day to use data in Europe as part of the network’s Pay & Go Travel deal.
39 destinations are included, with allowances ending at 11.59pm each day.
However, O2 charges 16p to make calls to the UK or within Europe and 4p to receive. Texts cost 5p to send.
Compared with rival networks, O2 lags well behind at the moment. But that could change in future, as competition heats up.
EE has a wide range of packages available for travellers. These are split into all–round deals for calls, texts and web access and simple data plans for those who want to access maps and other web–connected services.
£4 per day will get you calls, texts and data in 47 destinations as part of its EuroPass. As with other networks, this is limited to UK allowances.
Making calls to numbers in the country you are in will cost extra. You only need to text 'EUROPASS 150' before you leave.
Travellers to the United States can pay £3 extra for access to the mobile web, or opt into a bolt–on as part of their monthly contract. Find out more here: EE roaming in the USA.
Virgin Media offers a number of Travel Passes.
These start at £1.40 for 10MB of data, rising to £6 for 50MB of data and £20 for 250MB.
While the pass does last thirty days, the reality is that 10MB of data will be used up within a matter of minutes on any modern smartphone.
For us that fact, combined with Virgin’s roaming packages are nowhere near as good as those of the competition.
You can check them out for yourself here: Virgin Media roaming packages.
So which is best?
Of all the major networks, Three is probably the standout provider when it comes to using your phone abroad.
Vodafone has excellent packages which cover a broad range of destinations, while EE’s service is decent.
O2 and Virgin aren't bad by any means. But they have a lot left to do if they want to be up there with their rivals.