International cellular data usage is really expensive: $15 or $20 per megabyte

An American friend forwarded an expensive message from AT&T. He took his smartphone on a business trip to Canada, and didn’t think about it. Oops. Or rather, “Ouch!”

From: AT&T Customer Care for Wireless

High International Data Usage Alert

Our systems have detected that you are using a substantial amount of data internationally. Unlimited domestic plans do not apply when roaming internationally.

Our records indicate that you currently do not have a discounted international data plan. Data usage in Canada will be billed at $0.015 per KB (approx $15.00 per MB). Usage in all other countries outside of the US and Canada will be billed at $0.0195 per KB (approx $20.00 per MB).

Many Americans subconsciously think of Canada as part of the U.S. market. No. It’s not.

Traveling outside your domestic market with your smartphone? Be sure to either arrange a discount plan with your carrier or turn off cellular data roaming. In any case, when you want to check email or surf the Web, use the smartphone on a WiFi network as much as possible, as even the discounted cellular plans are costly.

• Here are details about AT&T’s data packages for smartphone and laptop usage outside the U.S.

• If you have an iPhone, here’s a specific iPhone Travel Tips page from AT&T.