by KYW’s Michelle Durham

It’s vacation season, and for many of us the cell phone, Black Berry or iPhone is a necessary carry-on. But if you don’t call your carrier before leaving for your trip overseas, you may be in for a rude awakening when you return.

iphone getty Going on Vacation? Beware of Cell Phone Roaming Fees

file photo by Alberto Pizzoli/Getty Images

AT&T spokesperson Adam Cormier says the fees can rack up quickly if you don’t call your carrier at least one week in advance and arrange for an enhanced plan for your mobile phone:

“It depends on where you are heading, how long you are travelling. There have been some instances, not necessarily with AT&T, with people incurring charges of upwards of $10,000 — that is certainly an extreme case.”

But he says you’ll see a big bump in your bill, if you don’t have the conversation, and it’s not necesarily for just talking, it can be for data access:

“Pretty much most At&T devices are already able to operate in more than 220 countries. Just stepping off the plane, your device is going to work.”

And those data charges will begin to accrue.

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