There are some gotchas. AT&T sells passes by the device, so it could get very expensive to connect your whole family. Also, the company might pull your Day Pass access if your international data usage goes beyond 50 percent of your plan for two consecutive months. This is meant more for typical vacations and business trips than extended stays.

How does it compare to other options? It's mixed, really. T-Mobile doesn't charge anything for international data use, but you only get LTE speeds in Canada and Mexico. It'll be a pokey 128Kbps everywhere else. Sprint has a similar offer, but you'll have to pay for full-speed data depending on where you go and how much you use. Google's Project Fi has the sweetest deal at $10 for every gigabyte you use, but you'll have to pay by the minute for calls when you're not on WiFi -- and of course, you can't use it with just any phone. The most analogous alternative is Verizon's TravelPass, which charges the same $10 per day unless you travel to Canada or Mexico (where it's $2 for most people).

The International Day Pass is certainly an improvement on Passport, and better than T-Mobile or Sprint if you insist on high speeds. However, it's likely not your first choice if you expect to spend a lot of time abroad, or if you just need the basics and would rather spend as little as possible.