
The iPhone makes any trip better. You’ve got your camera for capturing memories. You can fire up a game to kill time in airports and train stations. Your music is always handy. And of course Maps, Mail, Safari, and all the subway-mapping, restaurant locating, and airline-check-in apps that chomp data in order to do their stuff.

And when they say "substantial roaming charges," they mean it.
But if you’re traveling overseas, you’re going to need a plan for where that data will come from--if you rely on your iPhone’s AT&T connection, you’re going to need deep pockets. Because while nationwide network access is included in your monthly data plan, when you go abroad your phone is connecting to another company’s network, who charges AT&T, who passes hefty fees on to you. You’ll pay 2 cents per KB (1.5 cents in Canada), which can add up quickly. For perspective, going over your DataConnect plan’s limit here in the U.S. will only ding you 5 cents per MB (with DataConnect 5GB) or 10 cents per MB (with DataConnect 200MB), so those KB are up to 400 times more expensive overseas. Ouch.
But it doesn’t have to be that way. Follow this advice and you can have a great time on vacation and avoid an astronomical data bill later.
Difficulty Level: Easy
What You Need:
>> iPhone with AT&T service
>> A desire to not get ripped off

Tap Reset Statistics before you leave so you'll know how much data you've used on your trip.
If you’re staying Stateside, don’t worry about it. As long as you’re getting cell service that can get you online, you’re good--all the iPhone plans include nationwide data access. If you’re on a limited DataConnect plan (5GB or 200MB), you might want to clear your usage stats (in Settings > Usage) before your trip, so you can keep an eye on how much you’ve used, since your usage might be heavier than normal during a trip.

If you're close to the end of your data allotment for the month, turn it off.
If you’re worried about using too much and going over your DataConnect plan’s limit, you can confine your phone to Wi-Fi by turning the cellular data off entirely, while leaving on the Wi-Fi. That option is in Settings > Network. Just slide Cellular Data to Off. You’ll still be able to make and receive phone calls anywhere, and your data-using apps will still work under Wi-Fi.

The phone even warns you that you should have this turned off when abroad.
This is where you hear the nightmare stories about people racking up thousand-dollar bills by innocently checking their email and Facebook pages too often on a European holiday. So turn off Data Roaming, in Settings > Network. You’ve got a few options for how to get online at that point.

Just head to a convenience store or mobile-phone shop when you arrive.
One option is to pick up a prepaid SIM card when you get to your destination, one that works for data as well as voice. Make sure to buy the right size. The iPhone 4 uses a microSIM, but the other three iPhone models use regular-sized SIMs.

Sign in to Boingo's iPhone app once, and just launch it to auto-connect to Boingo hotspots.
Another way to get your phone online without roaming is to subscribe to a Wi-Fi service like Boingo Mobile (mobile.boingo.com), which has a $7.95/month account for unlimited access at 125,000 hotspots in 70 countries. Other companies provide the same service, but Boingo hits a sweet spot between price and widespread availability. To scope out hotspots before you travel, check out JiWire’s site at jiwire.com, or grab their free iPhone app.
Follow this article's author, Susie Ochs, on Twitter.