“What is the cheapest way to connect overseas?” a friend recently asked. “You’re in luck,” I told her, “International roaming just got much better for US mobile customers who travel.”

If you’re one of the 67 million Americans who travel globally, changes in international roaming plans mean you no longer need to “turn off data roaming” outside the U.S. and search for Wi-Fi hotspots. In 2013, T-Mobile disrupted the international roaming market with the launch of “unlimited international data and text services.” Since then, other U.S. mobile operators began offering improved, lower-cost international roaming plans, for the first time allowing full use of your smartphone outside the U.S. Global travelers who rely on mapping, social media, travel, booking, or ride sites don’t have to wait to get to their hotel wi-fi network to check email, upload pictures or plan the next leg of your trip.

This is a guest post by TravelSkills reader and telecom expert Whitey Bluestein

Americans are traveling more than ever. Last year, nearly 67 million traveled to international destinations, an overall increase of 8 percent over the previous year. While more than half traveled to Mexico or Canada, Europe was the most popular destination outside North America, with nearly 12 million Americans traveling “over the Pond.” Europe was followed by the Caribbean (6.6 million) and Asia (4.4 million), according to data from the National Travel and Tourism Office. For mobile operators, these travelers are typically high-value customers whom carriers don’t like to tell “don’t use your phone or a feature” when traveling, and don’t want to receive angry calls over roaming charge “bill shock.”

I put one of the plans to the test just last week, and for the first time ever, I used my smartphone in Europe, including my favorite apps, without fear of roaming charge shock. Google Maps, Facebook, Instagram, Flickr, Twitter, Email, TripAdvisor, Booking, Uber and OpenTable all worked great in Europe, wherever I was. It’s a great time to travel!

How do these international plans stack up? Here’s how each of the mobile operators describe their international roaming plans.

Verizon TravelPass

Verizon’s TravelPass allows use of your domestic talk, text and data allowances while traveling outside the U.S. for a flat daily rate. Instead of paying per minute, per message, or per MB, Verizon customers traveling to any of 100+ countries covered are charged a flat daily rate with TravelPass. For Mexico and Canada, the daily rate is $5/day, unless you have Verizon Plan Unlimited, which includes North America. In all other countries where TravelPass is available, the daily rate is $10. A “day” is 24-hours from when you arrive, turn your phone on, and use your phone; it then renews every 24 hours you use your phone. TravelPass is available on 4G LTE “World Devices” with GSM SIM, including smartphones, tablets, and mobile hotspots, among others. Note that 4G data speeds apply for the first 512 MB/day with reduced speeds thereafter, so make sure you do not have notifications or apps running in the background that consume data. (I exceeded this allowance on several days, and found that “reduced speed” was a crawl at best but more often, the spinning circle of death.)

You should enable International Services on your account, and there are other rules, so talk to a Verizon representative to make sure you’re on the right plan before you leave.

AT&T International Day Pass

With AT&T’s International Day Pass, subscribers can use their Mobile Share or AT&T Unlimited Plan for a flat daily fee while traveling in more than 100 countries covered. Instead of being charged per minute, message, or MB, subscribers pay a daily flat rate of $10/day per device for each 24-hour period. AT&T customers get unlimited talk within and between International Day Pass countries and back to the U.S., unlimited text, and use of the data plan that you use here in the U.S. Unlike other roaming plans, AT&T did not appear to have a daily limit on data, and subscribers get unlimited Wi-Fi access at participating hotspots in select countries via the AT&T Global Wi-Fi app. Although charges won’t be incurred until you use your phone abroad, you should add International Day Pass to each device prior to traveling abroad. Once you add International Day Pass, it remains active for future travel outside the US. Again, talk to your AT&T representative before you leave to make sure you’re on the right plan.

T-Mobile Simple Choice and T-Mobile ONE Unlimited 

T-Mobile offers unlimited data and texting in more than 140 “countries and destinations” at no extra charge for customers enrolled in Simple Choice or T-Mobile ONE unlimited plans. Note that unlike the AT&T and Verizon plans, international talk is extra, and this is not high-speed LTE but 128kbps, which is not recommended for streaming music or video. For higher data speeds, customers can add ONE Plus International for $25/month to get up to 256kbps speeds and other features. T-Mobile’s New Classic and Select Choice plans also provide unlimited text and data. There are no day passes or enrollment requirements, provided only that you are a T-Mobile subscriber on either Simple Choice or T-Mobile ONE. Unlike other plans, higher speed data is not necessarily included. “Free” roaming on T-Mo still has limitations. For example, you may need to add an On Demand Data Pass to get higher speed data, which has a daily rate like the other carriers’ plans. Voice calls are still rated and charged; only data and texts are free. Talk to a T-Mo representative to make sure you’re on the best plan available to meet your needs.

Sprint Global Roaming and High-Speed Data Roaming Pass

Sprint Global Roaming includes low-speed data and 20 cents/minute international calling, and is available at no extra cost if you have an LTE/GSM capable smartphone. If you want LTE data speeds, you will need a High-Speed Data Roaming Pass for single day and weeklong high-speed service, for $2/day or $10/week in Canada and Mexico, $10/day or $50/week in China, and $5/day or $25/week in Europe and “most other destinations.” Customers enroll by clicking a confirmation to the “Welcome SMS” travelers receive when they reach their destination outside the U.S. Sprint requires customers to remove all other international roaming add-ons (including Sprint Global Roaming), some of which may not be available when you return.

How Do the Plans Compare?

AT&T International Day Pass has a slight edge because unlike Verizon, there is no “throttling” when data usage exceeds 512 MB/day, virtually all AT&T devices are compatible and global Wi-Fi access is available via the AT&T app. At a cost, AT&T, Verizon and Sprint offer higher data speeds than T-Mobile, which includes lower data speeds for free or very little by comparison. In fact, T-Mobile has the lowest cost data roaming and messaging costs if you don’t need fast data speeds. Sprint’s daily and weekly rates, especially for Europe, are lower than AT&T’s or Verizon’s daily rates, and like AT&T, don’t include daily usage restrictions. The U.S. market is highly competitive, and rates (and promotions) change frequently, so the best strategy is talk to your carrier representative before you embark.

Will my smartphone work where I’m traveling? Most recent smartphones are quad-band, which mean they should support the frequencies in most travel destinations. For Verizon and Sprint, it must be a world phone with LTE/GSM, available on most newer high-end smartphones. If you have a flip phone or older (3+ years old) smartphone, it might be time to upgrade before your trip. And don’t forget your charger and conversion plugs.

Make sure you’re on the right plan, and then don’t touch that Data Roaming switch. Enjoy your trip, your smartphone and your favorite apps!

NOTE: The above is based on plan descriptions on the carriers’ websites. It is difficult to make “apples to apples” comparisons of plans, which may include “promotions” that may not be available when you call. Talk to a carrier representative well before your trip to confirm that you are on the right plan, have a compatible device, and know what your data speeds, availability and costs will be.

Whitey Bluestein, a 35-year telecom veteran, is a strategic advisor and corporate development executive focused on connected cars/devices, M2M, mobile applications, payments, roaming and voice recognition. He is a CNBC mobile industry expert and 2013 Mobile Power Player.

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