Roaming vs eSIM: The Truth About Using Your Phone Abroad

You land at Heathrow Terminal 2, bags still on the carousel, running on bad plane coffee and optimism. The first thing you want to do is open Google Maps, text someone that you landed, and figure out where that Airbnb you booked actually is.

So you flip your phone off airplane mode.

It connects, the maps load, messages send and you feel like a competent traveler. Over the next few hours you use your phone for directions, a restaurant lookup, and a few Instagram Stories from a rainy London street that somehow looks cinematic anyway.

Three weeks later, you're home and you open your Verizon bill.

$400. Maybe $600. Maybe $900.

Nobody warned you... Your phone just worked. What you didn't know is that the second you came off airplane mode on British soil, your carrier started racking up charges at a rate nobody told you about, and you had zero indication it was happening in real time.

This post is going to explain exactly what's going on, show you what your local carrier (i.e. Verizon, AT&T, and T-Mobile) actually charge for international use, and walk you through what most experienced travelers do instead. By the time you're done, you'll know what to buy (ehemm, looking at you Nomad eSIM), how to set it up, and (critically) how to make sure your home carrier isn't quietly charging you in the background while you use it.

What Actually Happens When You Roam

Roaming sounds technical, but it's actually pretty simple.

When you're in the US, your phone connects to your carrier's towers: Verizon's, AT&T's, T-Mobile's, whoever you're with. Your monthly plan covers all of that without any surprises.

When you land in the UK, your carrier doesn't have towers there. So your phone automatically latches onto a local network, like EE, Vodafone, or O2... this is "roaming," meaning your phone is borrowing a British network to stay connected.

Here's where it gets expensive. The British carrier charges your US carrier for that borrowed connectivity. Your US carrier then marks it up, adds their own margin, and passes the total cost to you. There are two companies making money every time you load a webpage. Neither of them is motivated to warn you in real time as charges pile up.

If you're on a standard plan with no international add-on, you're on pay-as-you-go rates. Verizon's pay-as-you-go international data runs around $2.05 per MB in many countries... and that's per megabyte, meaning streaming a single minute of YouTube can cost $20 or more. A few hours of normal phone use (Maps, messages, Instagram, a restaurant search) can add up to hundreds of dollars before you've finished your first pint in a London pub.

Your phone often doesn't warn you, it just connects and runs in the background until you get home and open your bill.

Roaming Horror Stories

These aren't cautionary tales made up to scare you. They're real, documented cases. The first one involves my own family.

The Company Phone That Cost $900

A relative of mine was traveling from the US to the UK for work on a company phone. He landed, turned it on, and used it normally for one day: emails, Maps, a few calls... standard work stuff.

The company received a bill for over $900 for that single day.

He didn't pay it personally (it came out of the company's budget), but he spent a few days in awkward conversations about it. The phone was never set up for international use and nobody thought to check before the trip... one day of normal use, $900.

The Verizon Family of Four

A family of four planned a 3-week trip to Europe. Before they left, they called Verizon and confirmed their phones were unlocked and ready for international travel... Verizon said they were good to go. Nothing worked as expected when they arrived.

They spent over 4 hours on hold with Verizon customer service across two days. Reps gave them random codes to try, then hung up. Nobody solved the problem. The family ended up paying nearly $500 in international charges over the 3 weeks, despite having been told they were covered. Multiple accounts of near-identical situations turn up on Reddit and carrier complaint forums.

The $143,000 T-Mobile Bill

A man from Florida came home from two weeks in Switzerland to find a T-Mobile bill for $143,442.74... and yes, this one made the news. He had used his phone to send photos and messages to family and friends, normal vacation behavior. He'd consumed 9.5GB of data over the trip. He'd been told before he left that he'd be covered. His lawyer eventually got T-Mobile to credit the entire amount, but it took legal intervention to make that happen.

$143,000 for vacation photos and group chats. These aren't urban legends. They're reviewable on Reddit, news articles, and carrier complaint forums.

Your Options: What You Can Actually Do

When you're planning an international trip, you have three real options for staying connected.

Option 1: Do nothing. Leave your plan as is and assume it'll sort itself out. This is the horror story option. Pay-as-you-go international rates are brutal, your carrier won't notify you as charges rack up, and you find out the total when you get home.

Option 2: Add an international plan from your carrier. Better than Option 1. All three major US carriers offer international add-ons, daily passes, or monthly plan upgrades. You won't get a $900 single-day bill, but you're still paying significantly more than you need to. More on the exact costs below.

Option 3: Get a travel eSIM. An eSIM is a digital SIM card that you install on your phone before you travel. You buy a data plan for your destination or region, it activates when you land, and all your data runs through it while abroad. Much cheaper than carrier add-ons for most trips, no physical SIM swap needed, and you keep your home SIM active for calls and texts.

Let's look at what each carrier actually charges, so you're not guessing.

What the US Carriers Charge for International Plans

Verizon

Verizon has two main paths for international travel.

TravelPass costs $12/day in 210+ countries (including most of Europe), or $6/day in Canada and Mexico. Each day gives you 5GB of high-speed data, after which speeds drop to 3G. The "day" clock starts when you first use your phone abroad, not at midnight.

$100 International Monthly Plan covers unlimited data (20GB high-speed, then slower), unlimited texts, and 250 calling minutes. If you're away for 9 days or more, this is cheaper than TravelPass.

Without any plan at all, Verizon's pay-as-you-go rates are around $2.05 per MB in most international markets. Don't go this route.

Here's a real complaint from a Verizon customer, sourced from their community forums:

Verizon has the daily charge of $10 if you use your phone internationally... AS long as your phone is on when you are outside of the US, you get charged for $10 a day... You won't even get notifications for the charges. After about 2 hours on call with customer service, we get credited $100 for a total charge of $218... The level of stress and frustration is beyond expression.

Note: this was written when the rate was $10/day. It's now $12/day.

T-Mobile

T-Mobile bakes some international coverage into its higher-tier plans, which distinguishes it from Verizon and AT&T.

Experience More ($85/month): Unlimited text plus 5GB of high-speed data in 215+ countries. If you're already on this plan and your data use abroad is light, you may not need anything extra.

Experience Beyond ($100/month): Unlimited text plus 15GB of high-speed data globally.

AT&T

International Day Pass is AT&T's main option, at $12/day in 210+ destinations (or $6/day per additional line on the same account). It pulls from your existing domestic plan data rather than a separate international bucket.

There's one genuinely useful detail about AT&T's structure: charges are capped at 10 daily fees per billing cycle, meaning $120 per line maximum. After that cap, you get unlimited high-speed data for the rest of the billing period. For long trips, that's actually competitive.

For use on cruises or at sea, the rate jumps to $20/day.

Comparing the Options: Real Trip Scenarios

Which option is cheapest depends entirely on trip length, number of lines, and how much data you need. These tables lay it out clearly.

Use code THEFABRYK for 15% off regular-priced plans over $5 at checkout (excludes Unlimited plans, valid until Aug 31, 2026), which brings all of these prices down further.

Quick Trip (1–3 Days)

Winner: Nomad eSIM by a wide margin if you just need data and can use WhatsApp or FaceTime for calls. Verizon or AT&T only if you need your US number for incoming calls.

10-Day Trip (Most Common)

Winner: Nomad eSIM wins by a wide margin on cost. AT&T or Verizon only if you need your US number active for incoming calls throughout the trip.

30-Day Trip

Winner: Nomad eSIM on price for most travelers. The one exception worth noting: AT&T's $120 cap on a month-long trip gives you unlimited high-speed after the cap, which is genuinely hard to beat if you're a very heavy data user. But for most people, 10–20GB for €20–24 is more than enough.

Traveling with a Partner

AT&T has one angle here that's worth knowing: additional lines on the Day Pass cost $6/day instead of $12. With the 10-day billing cap per line, two people traveling for a full month would pay $120 (first line) plus $60 (second line) = $180 total, with unlimited high-speed after the cap. That's competitive.

BUT two Nomad eSIMs for the same month in Europe would run roughly $23–27 each, so about $46–54 total. Still significantly cheaper, and that's without the THEFABRYK discount code applied (15% off regular-priced plans over $5, excludes Unlimited plans, valid until Aug 31, 2026).

One thing these carrier comparisons don't account for: most trips to Europe go to a handful of countries. Italy, France, Spain, Portugal. You don't need a plan covering 215 countries. A Nomad Europe regional eSIM covers all of continental Europe for much less than any global carrier add-on. If you're spending 10 days between Rome and Barcelona, paying for international coverage in 200+ countries you'll never visit doesn't make a lot of sense.

Why We Use Nomad eSIM

We run this blog from between Berlin, Italy and everywhere else we find ourselves around the world, and eSIMs have been part of our logistics for years. Not because they're trendy but because they're cheaper and easier than every alternative we've tried.

We use Nomad eSIM regularly, including within Europe. I just recently used a Nomad Europe-wide plan while moving between Germany and Italy earlier this year. No setup issues, 5G coverage in both countries, and when I had a question about switching devices mid-trip, customer service responded quickly with an actual answer (not a canned reply). The app is clean, the QR code install takes about 2 minutes, and you don't need to be particularly tech-savvy to get it working.

A few things that stand out compared to other eSIM providers: Nomad has unusual regional plans that most providers skip... China, Japan, South Korea or the Caribbean, for example. If you're traveling somewhere less common, they often have a plan for it. And the free 1GB trial plan (no credit card required) is a low-stakes way to confirm compatibility before your trip.

Nomad Europe Pricing

Let's take a look at the cost of the regional European package to show much you really could be saving.

Nomad Italy Pricing

If you're specifically heading to Italy and already have regional coverage handled elsewhere, Nomad's Italy-specific plans are even cheaper:

To put that in perspective: a 3GB Italy plan for 30 days costs $7, while a single day on AT&T's Day Pass costs $12.

eSIM Pros and Cons

Is Your Phone Compatible?

Most modern smartphones support eSIM. Here's how to confirm yours does.

iPhone: Most iPhones from the iPhone XS (2018) onward support eSIM. To check, go to Settings > Mobile Service and scroll down. If you see "Add eSIM" there, you're compatible.

To check whether your phone is carrier-locked: go to Settings > General > About > Network Provider Lock. If it says "No SIM restrictions," you're unlocked and can use any eSIM. If it says "SIM locked," read the section below before assuming you're stuck.

Most iPhones bought outright or fully paid off on installment plans are unlocked. Phones still under an active carrier financing contract may still be locked. If you're unsure, call your carrier and ask directly.

Android: Samsung Galaxy S20 and later, Google Pixel 3a and later, and most flagship Android phones from 2020 onward support eSIM. To check: go to Settings > Connections > SIM Manager. If you see an option to "Add eSIM" or "Add mobile plan," your device is compatible.

The carrier lock check on Android varies by manufacturer. The quickest path: call your carrier and ask whether your specific device is unlocked for international use.

What If Your Phone Is Locked?

Locked doesn't necessarily mean blocked. The reality is more nuanced than most people realize.

A carrier-locked phone is programmed to accept SIMs only from the selling carrier (and their approved partners). But on dual-eSIM iPhones (iPhone 13 and later), the secondary eSIM slot often has fewer restrictions than the primary line. Many travel eSIMs, including Airalo and Nomad, work as a secondary eSIM on locked phones, even if a local carrier SIM would be blocked outright. It's not guaranteed, but it works often enough that it's worth testing before your trip.

Unlock timelines, by carrier:

• Verizon: Phones are automatically unlocked after 60 days by FCC agreement. If you've had your Verizon device longer than that, it's likely already unlocked.
• AT&T: Locked until the device is fully paid off or the contract is completed. Primary line must remain AT&T until then, but the secondary eSIM slot shows more flexibility.
• T-Mobile: Requires 40 days of active service before unlock eligibility.

How to unlock: All three carriers let you submit an unlock request online (no store visit required). Once approved (usually within 24 hours), the phone unlocks automatically over a cellular connection. Requirements are the same across carriers: device fully paid off, account in good standing, and minimum time on network met. If you're deployed military, you can request expedited unlocking.

One practical note: iOS updates have quietly improved eSIM compatibility on locked iPhones over time. What didn't work on iOS 15 or 16 may work on iOS 17 or later. If you have a locked phone, keep it updated to the latest OS before testing.

If you're buying a new phone and plan to travel frequently, pay the extra cost for an unlocked device upfront. The flexibility is worth it. If you're already locked, check your eligibility now — most people qualify for unlocking sooner than they think and never request it.

How to Set Up a Nomad eSIM Step by Step

This is easier than it sounds. You can have it installed and ready before your flight departs.

Step 1: Buy Your Plan

Go to nomadesim.com (or download the app), choose your destination (a Europe regional plan covers the whole continent, or pick a country-specific plan if you're staying put), and pick your plan size. For a 10-day Europe trip, 3GB is usually enough for most travelers. 5GB if you're navigating a lot or posting frequently. Use code THEFABRYK at checkout for 15% off regular-priced plans over $5 (excludes Unlimited plans, valid until Aug 31, 2026).

Not ready to commit? Try the free 1GB trial plan first... no credit card required.

Step 2: Check Your Email

Nomad sends a QR code to your email after purchase. Keep that email accessible, you'll need it for the next step.

If you are using the app, the eSIM you have just purchased will already be in the app.

Step 3: Install the eSIM Before You Travel

On iPhone: Settings > Mobile Service > Add eSIM > Use QR Code. Scan the QR code from Nomad's email or to make things easier, just follow the instructions in the email or app to install the eSIM.

This page generally gives you the most updated info on how to go through the install process in case you are confused.

On Android: Settings > Connections > SIM Manager > Add eSIM. Scan the QR code.

Do this while you're still on Wi-Fi at home, since you don't need cellular service to install an eSIM.

Step 4: Don't Activate It Yet

Install the eSIM but leave it inactive until you land. Nomad's plan starts counting from when you first use data, not from when you install it. Installing it before departure costs you nothing.

The Most Important Step: Turning Off Roaming So You Don't Get Charged Anyway

This is the step most people miss. And it's where things go wrong.

A lot of travelers install an eSIM and still get roaming charges on their home carrier bill. Not because the eSIM didn't work, but because their home SIM was still running data in the background while the Nomad eSIM also ran data. Two lines, two sets of charges.

Here's exactly how to prevent that on iPhone.

The goal: Keep your main SIM (Verizon, AT&T, T-Mobile, etc.) active for calls and texts so people can reach you on your US number, but force all data through your Nomad eSIM and make sure your home carrier isn't roaming data at all.

Step-by-step for iPhone:

1. Go to Settings > Mobile Service
2. Tap your primary line (your home carrier)
3. Turn Data Roaming OFF for your primary line
4. Go back to Cellular settings
5. Tap "Mobile Data" and switch it to your Nomad eSIM (you will have given it a label in the previous step)
6. Turn Data Roaming ON for the Nomad eSIM
7. Turn "Allow Cellular Data Switching" OFF. This is the critical one. If this is left on, your iPhone will secretly fall back to your main carrier line whenever the Nomad eSIM signal dips, triggering roaming fees on your home plan without any notification.

Once those steps are done, your US number works for calls and texts, all data runs through Nomad, and your home carrier won't be roaming data at all.

Option 2 (simpler, but you miss calls on your US number):

If you don't need your number active while abroad, just turn off your primary line entirely. Settings > Mobile Service > tap your main line > toggle it off ('Turn on this main line'). Your Nomad eSIM handles everything. The downside: people trying to call your US number won't get through while you're away.

Note for iMessage users:

After installing your eSIM, you may need to reset iMessage so messages route correctly. Go to Settings > Apps > Messages > toggle iMessage OFF then back ON. Tap Send & Receive, uncheck your phone number, and make sure your Apple ID email is checked instead (sometime it takes a little while for it to pop up). This lets iMessage run over data without requiring your US carrier number to be active.

For Android:

The steps vary by manufacturer, but the principle is the same: disable data roaming on your primary SIM, set your eSIM as the default data SIM, and disable automatic SIM switching. If you're unsure, search your specific phone model plus "disable data roaming on primary SIM" and you'll find a step-by-step for your exact setup.

FAQ

Final Verdict

You know what roaming is now. You've seen what it costs when it goes wrong ($143,000 for vacation photos, $900 for one workday, $500 for a family trip Verizon said was covered). You've seen what your carrier charges when you plan ahead: $12/day from Verizon and AT&T, $85–$100/month from T-Mobile, even for a 10-day trip.

And you've seen what a Nomad eSIM costs for the same trip: a 10-day Europe trip on a carrier add-on runs $85–$120, while a Nomad eSIM with 3–5GB costs €10–15 (~$11–16). It's not even close.

The only real reason to use your carrier's international plan is if you absolutely need your US phone number active for incoming calls the whole time you're away. For everyone else, a Nomad eSIM handles everything you need at a fraction of the cost. Set it up at home before you leave, follow the steps to turn off data roaming on your main line, and your phone works exactly as it does at home without the bill shock on the other side.

If you want to test it before committing, Nomad's free 1GB trial exists for exactly that reason... no card, no commitment required.