[Photo/The New York Times]

It's hard not to feel ripped off when you get hit with unexpected roaming charges while traveling abroad - whether they come from making phone calls or checking e-mail. Take it from Jeff Gardner, who received an $11,000 bill from Verizon after spending four days in Jamaica. Before the trip, Mr. Gardner, who runs a fly-fishing business in Grayling, Mich., said he called Verizon to find out what it would cost to use his cellphone for calls and his wireless air card to check e-mail on his laptop while in the Caribbean. He said he was told that calls would be about $2 a minute and that there would be no extra charges for data as he was on an unlimited plan. The latter part turned out to be wrong.

"I don't mind paying a fair amount for fair service, but $11,000 for four days is ridiculous," said Mr. Gardner, who used his phone sparingly on the trip. He also tried to check and send e-mail using his laptop's wireless card, but quickly gave up after the e-mails didn't go through. Still, his Verizon bill said more than 500,000 kilobytes of data was transferred while he was in Jamaica, an amount Mr. Gardner said is 100 times what he normally uses in a month.

As travelers increasingly use smartphones abroad in the same way they do at home - to check e-mail, update Facebook and Twitter and pull up online maps - many are facing costly roaming fees, which providers charge when customers use their phones outside their service area. In fact, roaming charges have gotten so out of hand that the Federal Communications Commission has proposed a plan that would require wireless companies to send their customers a voice or text message when they are approaching their plan's limit, when they have reached that limit and when they are starting to incur roaming fees. A survey by the commission found that one in six mobile users have experienced "bill shock" from unanticipated roaming charges or other confusing fees.

Carriers say they already offer alerts via text message or e-mail when consumers approach or go over certain usage thresholds. But the Federal Communications Commission says such warnings vary widely by provider and type of service covered and that consumer protection is insufficient. When Mr. Gardner complained to Verizon about his $11,000 bill, for example, the carrier told him he was repeatedly sent roaming alerts via text and e-mail. But he never got the alerts since his cellphone and e-mail didn't work in Jamaica.

Thomas Pica, a Verizon spokesman, said, "We send a welcome message to our customers informing them of international rates where they are roaming as well as text alerts," and added that the carrier just expanded those alerts to begin when a customer hits $25 and continue at different increments to $1,000 and then again every $1,000 after that.

So how do you avoid the charges? This week's column tackles phone calls. Next week's will look at everything else - from checking e-mail to using online maps and updating Facebook and Twitter - all of which involve transferring costly data. Below, Part 1 of the Practical Traveler's guide to bulletproofing your wireless bill while abroad.

SIM CARDS FOR LOCAL CALLS

The cheapest way to make local calls while abroad is to use an unlocked cellphone that can work with other carriers' networks, along with a prepaid local SIM card - a removable chip that determines the phone's network and number. "You'll always save a lot more money doing that than using the roaming rates from your carrier," said Charles S. Golvin, an analyst with Forrester Research. In general, incoming calls will be free and making local calls as well as sending texts will be cheaper.

First, ask your carrier if your phone can be unlocked. Customers of AT&T and T-Mobile will have the best luck with this because their signals are compatible with more foreign carriers. Most cellphones that operate on Verizon and Sprint aren't compatible with networks outside the United States, making unlocking beside the point. If you use one of those carriers, decide whether it's better to pay the carrier's roaming rates and simply limit calls or buy a basic, unlocked phone for calls and texts (which can usually be found for $40 or so) in the country you're visiting.

If you arrive with an unlocked phone, purchase a prepaid local SIM card (typically $20 or so) and pop that in the phone to make calls at lower local rates. Travelers who want the security of having a SIM card before they land can buy one at sites like Telestial.com or OneSimCard.com, whose prepaid local SIM cards offer rates lower than most American carriers. For example, Telestial's $39 "TIM" SIM card for Italy comes with about $7 (5 euros) of airtime credit, free incoming calls and rates of about 14 cents per call and 21 cents per text for numbers within Italy. By contrast, Verizon's calling rates in Italy range from 99 cents a minute (with a Value Plan) to $1.29 a minute (with a Standard Plan). Sending a text costs 50 cents. Telestial also offers regional SIM cards, which offer low calling rates for multiple countries.