3 has barred customers from international data roaming to protect them from racking up massive bills abroad.
Customers will have to contact the network to request the service, but a £50 limit will still be put in place. Those anticipating high usage will have to request it, following a further credit check.
3 UK chief executive Kevin Russell said: “Due to the huge disparity in what we charge on our networks and the costs charged by many others for wholesale roaming in Europe, which we are forced to pass on to the customer, we have decided to make a data roaming bar the default for contract mobile broadband users.
“We have seen customers on other networks run up bills of more than £4,000 just for downloading a few TV shows. We have to draw attention to this, as the use of dongles is growing rapidly and many more customers are in danger of shock bills.”
The European Commission is currently consulting on the issue of excessive wholesale rates and has suggested a 35 Euro cents per megabyte wholesale rate across the EU.