The Ultimate Guide to International Smartphone Use

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We're all for disconnecting while on vacation. But sometimes — whether you're traveling for business or searching for directions — having an internet connection can be seriously useful, even crucial, when traveling abroad.

Not all that long ago, international travelers had to choose between paying exorbitant roaming rates from their US carrier, or worrying about securing and activating a local SIM upon arrival.

Today, things are mercifully different. There are more options, and it's more affordable than ever to stay connected abroad. Most major US carriers have adopted sensible pay-per-day rates to compete with T-Mobile and Google Fi, both of which disrupted the prior model of charging per-megabyte rates. (For reference, TPG himself was dinged by AT&T at $19.99 per megabyte in 2010 while roaming in London. He faced a $180 charge for essentially checking his email twice.)

In this guide, we'll take an in-depth look at what international roaming options exist on the major US carriers; when you should consider procuring a local SIM upon arrival; what an unlocked smartphone is (and who should consider one); and options for long-term travelers and backpackers.

Roaming With Major US Carriers

First, the good news: Every major domestic telecommunications company now offers international data roaming that isn't outrageously expensive. In some cases, throttled (read: slow) data usage is included gratis for a number of countries. Elsewhere, you're able to use your phone exactly as you would in the US for around $10 per day. For short-term stays and vacations, you should be in good shape.

If you want to avoid roaming charges altogether, be sure to leave your phone on Airplane mode even after you deplane. And if you simply want to avoid data roaming charges (but still want calls and texts to come through), visit the "settings" menu on your phone and toggle off Data Roaming.

AT&T

For $10 per day, per line, you can activate AT&T's International Day Pass (available exclusively for users on AT&T's Mobile Share or Unlimited plans, but unless you're a prepaid customer, chances are high your plan falls into one of those two buckets).

To check your eligibility, log in to your AT&T account and add the International Day Pass, if shown. Make sure to toggle for each line on your account. You won't be charged a dime until you turn your phone on while in a foreign country, and the $10 per day will be added to your bill automatically. Once AT&T detects you're back in the US, those $10 charges will automatically cease.

Unlimited calls are included within countries covered by International Day Pass (currently listed as "over 100") and back to the US, plus unlimited texts to the world. A big boon to AT&T's plan is the speed. Your speed overseas will not be throttled, so if you're in an LTE network zone, you'll enjoy LTE speeds. For Mobile Share plan customers, we recommend resetting the data usage counter on your phone upon landing to keep track of how much data you use overseas, as your international data usage will count against your monthly data allotment.

Pros:

• Effortless to add to your account
• Use your existing phone (no need to hunt for an unlocked one)
• No data speed throttling
• Take calls on your personal number at no extra cost

Cons:

• Mobile Share plan users have to monitor data usage
• $10 per day, per line, can add up quickly for families and long trips
• While over 100 nations are covered, many still aren't

Google Fi

While Google Fi isn't a "major" carrier in terms of mass awareness, it's a well-known option for frequent travelers. You pay $20 per month for unlimited calls and texts, and $10 per gigabyte for high-speed data. If you happen to use more than 6GB, Google's new "Bill Protection" kicks in to cap your data bill at $60 per month, covering further high-speed data usage up to 15GB per month. In the US, Google Fi latches onto whichever signal is the strongest between its three partner carriers: Sprint, T-Mobile and US Cellular.

The great news here is that Google doesn't differentiate between domestic data and international data, which makes it an outstanding value for long-term travelers and backpackers. Another major perk of using Google Fi overseas is the breadth of nations that are covered (currently, over 170). You won't find Pitcairn Island on the list, but certain African countries like Ivory Coast, Chad and Congo (DRC) are included with Google's plan, whereas they are frequently omitted by rival carriers.

Google Fi's primary limitation is its diminutive list of supported phones. Fewer than 10 phones are supported (all of which use the Android operating system), though the Pixel 2 and Pixel 2 XL are excellent devices if you're in the market for a new handset anyway. No, an iPhone won't (officially) work with Google Fi. There are workarounds if you have an unlocked iPhone, but you'll be limited to the T-Mobile network.

Pros:

• Google Fi treats international data just like domestic data
• Works in more than 170 destinations
• Monthly pricing with no contract or commitment
• The Google Fi-compatible Pixel 2 and Pixel 2 XL take amazing photos
• Take calls on your personal number at no extra cost

Cons:

• Even combined, Sprint, T-Mobile and US Cellular may not provide ideal coverage for you at home
• Very limited supported phone selection: you may need to buy a new phone

Sprint

If you aren't concerned with voice calling, Sprint's international roaming plan provides text and data coverage in more than 185 destinations. Sprint Global Roaming is included on postpaid plans with LTE/GSM capable smartphones, giving you text and 2G data coverage at no extra charge. Just fly, land and start using your smartphone as you normally would. Voice calls, however, will run you $0.20 per minute or more, so plan on making calls through Slack, WhatsApp or another platform that uses data rather than voice networks.

However, that little 2G detail means that while overseas, your data will be severely throttled to 128Kbps, which is too slow to stream videos on YouTube or engage in a non-glitchy FaceTime chat. Sprint does allow users to pay extra to enable LTE speeds abroad.

• Canada and Mexico: $2 per day or $10 per week
• Other destinations: $5 to $10 per day or $25 to $50 per week, depending on Sprint's partnership agreements in the nation you're visiting

The 2G data should be fine for checking email and navigating with Google Maps, but at least there's an option to pay for a faster path should you land and determine it's necessary. One other quirk: Sprint offers a dedicated Japan Plan for just $5 per month, which enables high-speed data roaming, texting and voice calls.

Pros:

• The best option for long-term travel in Japan
• 2G data speeds for free, with an option to pay more for faster access
• Rates are reasonable for those who frequent Mexico and Canada
• Support for 185-plus destinations

Cons:

• It's Sprint, which doesn't have the best US coverage
• International voice calls can get expensive, fast

T-Mobile

As with Sprint, T-Mobile's postpaid ONE plans include international texting and 2G data (capped at 128Kbps) for free in more than 210 countries. Sadly, the carrier recently nixed a $25 monthly upgrade to T-Mobile ONE Plus International, which included unlimited LTE hotspot access in the US; unlimited international calls to landlines in over 70 countries and mobile numbers in over 30 countries; unlimited 4G LTE in Mexico and Canada; and unlimited in-flight Gogo Wi-Fi within the US and boosted international data speeds to 256Kbps. It remains to be seen if T-Mobile will replace that plan with anything comparable.

Pros:

• 2G data (128Kbps) for free
• Reasonable rates for travelers who frequent Mexico and Canada
• Support for over 210 destinations (basically anywhere you'd be allowed to visit)

Cons:

• T-Mobile's coverage beyond major US cities isn't spectacular
• International voice calls can get expensive, fast

Verizon

Similar to AT&T, Verizon's TravelPass allows you to take your domestic talk, text and data allowances with you. You're only charged on the days you use your device abroad: $5 a day per line in Mexico and Canada, or $10 a day per line in over 130 other supported countries. And once you activate TravelPass on your lines, nothing else is required. As with AT&T, just keep an eye on your data usage if you're using a plan with a monthly cap. You'll also want to visit Verizon's list of supported nations to make sure the place(s) you'll be visiting are covered.

Pros:

• Verizon's US LTE coverage is fantastic
• Effortless to add to your account
• Use your existing phone (no need to hunt for an unlocked one)
• No data speed throttling
• Take calls on your personal number at no extra cost

Cons:

• $5 to $10 per day, per line can add up quickly for families and long trips
• While over 130 nations are covered, many still aren't

When to Buy a Local SIM Upon Arrival

If you're planning on being in a country for more than two weeks, you can expect to use a significant amount of data. It can also be helpful to have a local telephone number to call and text with residents and businesses. That's when having a local SIM may be right for you.

Local SIMs typically cost between $20 and $50, include between 1GB and 5GB of data (plus a sizable allotment of texts and voice minutes for in-country calling), and can be purchased at minimarts or vending machines at major airports. Once you have a SIM, you can typically "top-up," or add data, texts or minutes using your smartphone and a credit card.

It can be surprisingly easy, too. London-Heathrow, for example, has an automated SIM vending machine. But then there's the rest of the world — airports like Fa'a'ā in Tahiti — where you're as likely to ride a unicorn through immigration as you are to find a store that's open and selling SIM cards with English instructions when you land.

Still, if a local SIM seems like the option for you, you'll need an unlocked smartphone.

Getting an Unlocked Smartphone

A "locked" smartphone is chained to an exclusive carrier with software settings that can't be changed by the user. Generally speaking, if you purchase a phone from AT&T, T-Mobile, Verizon or Sprint (and still owe money on it) it's locked — and will remain that way. While it's locked, it will refuse to work with any SIM from another carrier.

An "unlocked" smartphone, on the other hand, will readily accept any SIM from any carrier, either domestic or international. If you maintain solid standing with your carrier and your smartphone is fully paid off, they will almost always provide an unlock code to customers who fill out an online request form. (To save you the trouble, they're linked here: AT&T, Verizon, Sprint and T-Mobile.)

Alternatively, you can order an unlocked smartphone directly from a manufacturer like Apple, Samsung, Huawei, Motorola or Google. You can also search for a gently used, unlocked smartphone on an auction marketplace. Just don't be surprised by the cost, as the flexibility to use them with any carrier results in premium pricing.

If you're planning a whirlwind tour of Europe or Asia, you'll undoubtedly cross borders. Each country has its own set of carriers and generally, a SIM purchased in one nation won't function in another. With an unlocked smartphone, you can swap prepaid SIM cards from various countries in and out as you travel. Many of these SIMs don't expire, so much like foreign currency, you could theoretically save SIMs with remaining credit to use whenever you return.

Still, having a single SIM from Google Fi is a far more elegant solution. But that only works if you're willing to hitch your wagon to the Android operating system.

Getting a Dual SIM Phone

Frequent flyers may also be interested in scooping up a Dual SIM smartphone, which can either hold two physical SIM cards, or, in some cases, a single physical SIM card with an additional onboard eSIM. This type of phone allows a user to initiate a call, text or use data with more than one carrier (versus just a single carrier).

Phones such as the Huawei P20 Pro, iPhone XS and iPhone XS Max, OnePlus 6, Samsung Galaxy Note 9, Asus Zenfone 5Z and Honor 10 all support dual SIMs, and that list is growing rapidly. This option is generally best for regular business travelers that consistently spend time in two countries (think: Canada and Germany). Keep in mind, however, that you'll need to pay for either data or a plan for both SIMs individually.

CDMA/GSM

There are two major, competing radio systems used by cell phones: CDMA (code division multiple access) and GSM (global system for mobile). In the US, only two of the major carriers (AT&T and T-Mobile) utilize GSM — but that's the network preferred by pretty much every other country on Earth. Verizon and Sprint operate on CDMA. However, most modern smartphones that support CDMA also have SIM card slots to support the LTE (Long-Term Evolution) network: the standard for data.

To cut down on the techno-babble, here's what most travelers needs to know: Very generally speaking, a GSM phone will be easier to transfer to a new network. But that's not to say it can't be done with a newer CDMA device. As long as the phone is unlocked and has a SIM card slot, it should work on a GSM network. To be sure your phone will be fully functional abroad — voice, data and texts — research the specific model of your phone and the bands it supports, and cross-reference that with the frequencies available in the countries you'll be visiting.

Using a Laptop Abroad

Many of the international plans mentioned support tethering — the function that allows your smartphone to share its data plan with other nearby devices like laptops.

That said, the 2G speeds offered by T-Mobile and Sprint won't cut it on a laptop, and both AT&T and Verizon will begin to throttle your speeds after you exceed approximately 22GB per month. Carriers are quick to notice prolonged tethering, and will typically take action on your account if you do it enough.

If having data internationally for use on a laptop is a primary concern, supplement whatever Wi-Fi you're expecting to have available with an international hotspot.

Skyroam, for example, offers a compact mobile hotspot for about $150. Once you have it, you can pay $9 per day or $99 per month for unlimited global data in over 120 countries to use on up to five devices simultaneously (phones, tablets, laptops, smartwatches). For travelers who can't take chances with coffee shop or hotel Wi-Fi, the hotspot also delivers peace of mind, and the puck itself also doubles as a charging device.

How to Choose the Right Option for You

Before deciding which phone to buy or network to choose, there are a handful of factors to consider:

• On an international trip for under two weeks, it's usually easier to use the day pass option provided by your carrier. If you also need data for a laptop, rent a Skyroam hotspot for the duration of your trip.
• On overseas trips longer than two weeks, travelers who already have an unlocked phone should see if the arrival airport sells local SIM cards. Travelers can also consider buying an unlocked phone for this purpose.
• Buy a Skyroam hotspot and carry it with you as you go, keeping your smartphone connected to data while you travel.
• If you're not married to a carrier already, consider the switch to Google Fi, as it's one of the best options for travelers.
• None of this advice really applies to cruising. Each carrier has their own rate charts for texting, calling and using data while at sea — and they're all pricey. For avid cruisers, you're better off paying for Wi-Fi once aboard.
• Whatever phone you end up using on your international escapades, be sure to use a card that offers cell phone protection, such as the Chase Ink Business Preferred Credit Card or Wells Fargo Cash Wise Visa® card (up to $600 of protection (subject to $25 deductible).

Do you have any other suggestions for staying connected abroad? Sound off in the comments below!