Fans going to the tournament with smartphones could face bills of more than £5,000 if they are not cautious about usage, according to research by price comparison site uSwitch.com.
In the Eurozone, mobile phone networks must cap mobile roaming call charges at 35p per minute. Receiving calls must not cost more than 11p, the same for sending texts.
There is also a 50 euro warning limit on the amount of data people can use per day while abroad, while a new data price cap and reduced calls/text charges will be introduced in the EU from July 1.
However, none of these restrictions apply outside of the Eurozone, meaning consumers will not be afforded the same protection while in the Ukraine.
Based on average cost calculations across the five major mobile networks, uSwitch said that using a mobile in Ukraine to make and receive just two five minute phone calls per day, as well as listening to a two minute voicemail message and sending five text messages and one photo message would rack up a bill of £35.
Mobile data in Ukraine costs an average of £6.10 for 1MB, meaning the average smartphone user could be stuck with a daily data bill of £228 for just a modest amount of video streaming, Skype, email and web browsing.
uSwitch feels that fans could face a total daily phone bill of £262 for calls, text and data - this means that anyone visiting Ukraine for the nine days from England's first group match on June 11 would come home to a bill of £2,362 on top of their usual monthly bill.
Those who stay in Ukraine until the final on July 1 could face a total bill of more than £5,500, 11 times more than the cost of a ticket for the final in the best seats, at £482.
USwitch.com technology expert Ernest Doku told PA: "Watching England might be priceless, but using your mobile phone abroad isn't. Footie fans have to think ahead as using their phones while following England could add more than £5,000 to what is likely to be an already expensive trip.
"The first thing England fans going to Ukraine - or indeed anyone taking a holiday outside the EU - should do is talk to their network.
"They may be able to advise a bundle, or at least let you know the costs involved with using your phone abroad. Those using their phone can help to limit the damage by keeping data roaming switched off as much as possible."
Doku said that O2 and Vodafone currently offer their pay monthly customers the opportunity to place an automatic cap on their data usage worldwide, while Orange, O2 and Vodafone all send out text alerts so customers can keep track of their usage.
"T-Mobile has told us it plans to introduce a new system to prevent customers from running up unexpected data bills abroad and hopefully this will be in place before Euro 2012 kicks off," he said.
"When it comes to calls and text messages, the best way to keep costs down to an absolute minimum is to buy a local SIM card, put it in your phone and top it up. Those mobile users wanting to go online should be on the ball and use free WiFi to help keep a lid on costs."