If, like me, you’re a smart phone user and you travel outside the country, you’ll need to figure out how to deal with your AT&T data plan lest you find yourself with a ridiculously high mobile phone bill. 

My best-known methods

Here are my current best practices (told through the lens of an iPhone user – if you use a different smart phone, you can make these changes by accessing your account through the AT&T Wireless web site):

• Install the free AT&T myWireless iPhone app on your phone.  This will let you change your account settings on demand, right from your phone.
• The day you leave (preferrably, while still in the US), use the app to add an international data plan to your phone (see screen shot).  You’ll notice I also turn on the “World Traveler” feature, which gets me discounted rates for calls while I’m traveling abroad.  These changes will go into effect the day you make the change, and will be pro-rated on your bill based on the start and end dates for each feature.
• Be careful while traveling abroad, as wireless data usage can mount quickly.  Some data hogs:
• Synchronizing your email, especially if you receive a lot of email
• Uploading pictures (whether to Twitter, sending via email, or otherwise sending them to anyone else)
• Using your phone for Skype calls over the 3G data network (using it over Wi-Fi is fine)
• Downloading large apps or songs over the 3G data network (again, not a problem on Wi-Fi)
• Using Google Maps a lot (it is very “chatty” and downloads lots of map data, etc.)
• Listening or watching streaming media (YouTube, internet radio, etc.)
• Use Wi-Fi (especially free hotspots) where you can, as this will allow you to handle large amounts of data in an unmetered way.
• When you return to the US, wait a day (just to be safe) then use the AT&T myWireless app to turn off the international data plan.  Again, you’ll pay a pro-rated fee based on the start & end dates for which the plan was in effect.

What if you forget?

AT&T has gotten better at helping users understand this, it seems.  I landed in Amsterdam this week and, upon turning on my phone and joining the mobile network, I received the following text message:

I was tired, so I ignored this message.  After a nap, I wandered around Amsterdam, looking up things on Google maps and Bing (yes, there’s an app for Bing), etc.  That evening I got second text message from AT&T:

Act Now!

When you get the “data usage is very high” message, it means you’ve gone over 20Mb of cellular data which, if you do the math, will cost you nearly $400! If you see this message, call the number immediately and ask them to add the International Data Plan to your phone right away!  If it’s before midnight in the US, the data plan will apply to all your usage earlier in the day, back to the previous midnight – this can help drastically reduce your charges (I happened to have only about $5 of data that wasn’t covered when I called them).

I’m documenting this here in the hopes I can make someone else’s international travel a bit less stressful.  Happy landings!