Summary

This article shows you how to check whether your phone can take a travel eSIM, choose between one and your carrier's roaming package, install it before you leave, and set the data and voice lines so you get cheap data abroad without losing the text messages your work account depends on.

In this guide

• 1. Confirm Your Phone Supports eSIM
• 2. Check the Rules for a Company-Managed Phone
• 3. Choose Between Carrier Roaming and a Travel eSIM
• 4. Move Your MFA Off SMS Before You Travel
• 5. Buy and Install the eSIM Before You Fly
• 6. Set Which Line Handles Data and Which Handles Calls
• 7. Turn Off Roaming on Your Primary Line

Before You Start

• A phone released in 2018 or later that supports eSIM, and that is not locked to a single carrier.
• A payment card and an internet connection at home, a few days before you travel.
• Permission to modify the phone. On a company-managed handset, this needs confirming — Step 2 covers it.

Instructions

1. Confirm Your Phone Supports eSIM

An eSIM is a SIM card built into the phone that is written by software instead of posted to you. Nothing goes in the tray. The check takes under a minute.

On an iPhone:

1. Open Settings > General > About.
2. Scroll to the bottom of the list. If you see a row labelled EID with a long number beside it, the phone supports eSIM. iPhone XS, XR and everything after has it.
3. While you are on this screen, find the row labelled Carrier Lock. It must read No SIM restrictions. Any other value means the handset is tied to one carrier and will refuse another provider's profile.

On Android:

1. Open Settings > Network & internet > SIMs. On Samsung Galaxy phones, open Settings > Connections > SIM manager.
2. Look for Add eSIM, Download a SIM instead?, or Add mobile plan. If one of those appears, the phone supports eSIM.
3. If nothing appears, open the phone dialler and enter *#06#. The panel that opens lists IMEI and, on eSIM-capable phones, EID.

Verification: An EID number on screen is the confirmation. It is the eSIM's own serial number, and phones without eSIM hardware do not display one.

Note: Carrier locking is separate from eSIM support and catches people out at the worst moment. A phone bought on a contract or instalment plan is often locked until the plan is paid off. If Carrier Lock shows anything other than No SIM restrictions, call the carrier and ask them to unlock the handset — most do it free once the account qualifies, and it can take a few days to take effect.

2. Check the Rules for a Company-Managed Phone

Do this before you spend money. If your employer manages the phone, the device policy can block adding an eSIM outright, and you find out at the point of installation.

1. On an iPhone, open Settings > General > VPN & Device Management. A heading reading MOBILE DEVICE MANAGEMENT with your company's name under it means the phone is managed.
2. On Android, open Settings and look for a Work tab at the top of the app list, or open Settings > Security & privacy > More security settings > Device admin apps. A listed work profile or admin app means the phone is managed.
3. If the phone is managed, raise a ticket now rather than at the airport. Send IT this wording: "I am travelling to my destination country on my departure date. Please confirm whether the device policy on my phone allows me to add a travel eSIM, and enable eSIM modification if it is currently blocked."
4. If the company pays the mobile bill, ask the same ticket whether an international roaming add-on is already on the line. Some employers prefer you use the corporate roaming package and will not reimburse a personal eSIM.

Note: Even on an unmanaged personal phone that carries work email, check your organisation's travel policy before you go. How to Set Up Your Work Profile on a Personal Device (BYOD) explains which parts of a personal phone the company can see and control.

3. Choose Between Carrier Roaming and a Travel eSIM

Both work. They are good at different things, and the difference is not only price.

	Carrier roaming package	Travel eSIM
Setup	Turn it on in the carrier's app, or nothing at all	Buy, install, and switch lines
Typical cost	A daily fee, often $10–$12 per day	A flat fee for a data bundle, often $5–$25 for a week or two
Your number	Keeps working normally	Usually suspended for data while it keeps ringing for calls
Calls and SMS	Included, at the package's rates	Nearly always data-only — no voice minutes, no texts of its own
Best for	Trips of one to four days, and anyone who must stay reachable on their number	Trips of a week or more, and data-heavy work

The trade-off worth reading twice: a travel eSIM is almost always data-only. It gives you a fast, cheap internet connection and no telephone service. Your normal number does not move to it. Calls and text messages to your usual number arrive only if you leave the primary line switched on, and the carrier charges its roaming rate for anything you answer or send.

That matters more than it sounds, because of one thing: text-message security codes. If your work account, your bank, or your airline sends a one-time code by SMS, and your primary line is off or restricted, the code never arrives and you cannot sign in. Step 4 fixes that, and it is the step to do first.

Everything that runs over the internet is unaffected either way. Teams calls, WhatsApp, iMessage, Slack and email all work over the travel eSIM's data.

4. Move Your MFA Off SMS Before You Travel

Being locked out of your work account in a different time zone is the expensive failure here. Switch your sign-in method to the Microsoft Authenticator app, which works over any data connection — including your travel eSIM.

1. On a computer, open https://mysignins.microsoft.com/security-info and sign in with your work account.
2. Click Add sign-in method, choose Authenticator app, and follow the prompts on screen. The full walkthrough is in How to Use the Microsoft Authenticator App.
3. Back on the Security info page, find the line reading Default sign-in method near the top and click Change beside it.
4. Select Microsoft Authenticator - notification and click Confirm.
5. Open the Authenticator app on your phone, tap your work account, and confirm a rotating six-digit code appears. That code is generated on the phone itself and works with no connection at all — it is your fallback if the travel data fails.

Verification: Sign out of Outlook on the web and sign back in. The prompt asks you to approve a notification in the app rather than asking for a texted code.

Tip: Do the same for personal accounts you rely on while travelling — the bank, the airline, and your password manager. If you are also changing handsets before the trip, How to Transfer MFA to a New Phone (Microsoft 365) covers moving the app across without losing access.

5. Buy and Install the eSIM Before You Fly

Installing an eSIM needs an internet connection, which is the thing you do not have when you land. Do this at home, on Wi-Fi, several days before departure.

1. Buy a plan from a travel eSIM provider covering your destination. Choose by country or region and by how many gigabytes you need — video calls run about a gigabyte an hour, ordinary email and maps far less.
2. After payment the provider emails you a QR code, along with a manual SM-DP+ Address and an Activation Code. Keep that email. Save a copy as a PDF or screenshot so you can reach it without a connection.
3. On an iPhone: open Settings > Cellular (Mobile Service on some regional builds) and tap Add eSIM. Tap Use QR Code, then point the camera at the code displayed on a laptop or printed page. If the camera cannot reach it, tap Enter Details Manually and type the SM-DP+ Address and Activation Code from the email.
4. On Android: open Settings > Network & internet > SIMs and tap Add eSIM or Download a SIM instead?. On Samsung, open Settings > Connections > SIM manager > Add eSIM. Scan the QR code and tap Download.
5. When the phone asks for a label, name the line something you will recognise — Travel works better than the default Secondary.
6. Leave the new line switched off. When the phone offers to make it your data line, decline for now.

Verification: The new plan appears in the SIM list under the provider's name with its own on/off switch. On an iPhone it sits under CELLULAR PLANS in Settings > Cellular.

Note: Installing is not activating. Most travel eSIMs start counting their validity from the moment the line first connects to a network in the destination country, which is why you leave it off until you land. A few start the clock at installation instead. The provider states which on the product page — read that line before you buy, not after.

6. Set Which Line Handles Data and Which Handles Calls

Do this after you land, once you have switched off airplane mode.

On an iPhone:

1. Open Settings > Cellular and tap the travel plan under CELLULAR PLANS. Turn on Turn On This Line.
2. Go back to Settings > Cellular and tap Cellular Data near the top. Select your travel line.
3. On the same screen, turn off Allow Cellular Data Switching. Left on, the phone quietly falls back to your primary line when the travel signal dips — at full roaming rates.
4. Tap Default Voice Line and select your usual number, so calls and texts still reach you on the number people have.

On Android:

1. Open Settings > Network & internet > SIMs and tap the travel eSIM. Turn on Use SIM.
2. Return to the SIMs screen. Under the preference rows, set Mobile data to the travel eSIM.
3. Set Calls and SMS to your primary number, or to Ask every time if you want to choose per call.
4. On Samsung, the same controls sit under Settings > Connections > SIM manager, in the Preferred SIM card section with separate Calls, Text messages and Mobile data rows.

Verification: The status bar shows two signal indicators. Turn Wi-Fi off and load any web page — it should come up over the travel provider's network, and the network name in Settings matches the provider you bought from.

7. Turn Off Roaming on Your Primary Line

This is the step that prevents the bill. Your primary line stays switched on so calls and texts still arrive, but it is barred from spending money on data.

1. On an iPhone: open Settings > Cellular, tap your primary number under CELLULAR PLANS, and turn off Data Roaming.
2. On Android: open Settings > Network & internet > SIMs, tap your primary SIM, and turn off Roaming. On Samsung, the switch is at Settings > Connections > Mobile networks > Data roaming.
3. On an iPhone, also turn off Wi-Fi Assist. Open Settings > Cellular and scroll to the bottom of the list. Left on, it silently switches to mobile data whenever Wi-Fi weakens, which is most of the time in a hotel.
4. Stop the background spending: turn off automatic app updates over mobile data, pause cloud photo backup, and switch app and system updates to Wi-Fi only. A single phone system update over roaming data costs more than the whole eSIM.
5. Answer calls with care. Incoming calls on a roaming line are charged in most countries even though the caller pays their own rate. Where you can, take the call over Teams or WhatsApp on the travel eSIM's data instead.

Verification: Turn Wi-Fi off and open a web page. It loads over the travel eSIM. Then open your carrier's own app — on the roaming-disabled line it fails to refresh, which confirms the primary line is no longer carrying data.

Tip: When you get home, reverse two settings and nothing else: turn Data Roaming back on for your primary line, and set Cellular Data or Mobile data back to that line. Leave the travel eSIM installed but switched off — most providers let you top the same profile up for the next trip instead of installing a new one.

Troubleshooting

WARNING

If your work account still uses text messages for sign-in codes, a data-only travel eSIM can lock you out of email entirely on the first morning of the trip. Complete Step 4 and switch to the Microsoft Authenticator app before you leave, while you are still on a network that can receive the setup text.

Symptom / Error	Potential Cause	Solution
Add eSIM is missing or greyed out	Device policy blocking eSIM changes	Confirm an EID exists (Step 1). If it does and the option is still unavailable, the phone is managed — raise the ticket wording in Step 2 and allow a few days for the policy change.
"Cellular Plan cannot be added" when scanning	Handset locked to one carrier	Check Settings > General > About > Carrier Lock. Anything other than No SIM restrictions means the phone must be unlocked by the carrier before any other provider's profile installs.
The QR code will not scan	Code already used, or screen too dim	An eSIM QR code works once. Use Enter Details Manually with the SM-DP+ Address and Activation Code from the provider's email. If the phone rejects those too, ask the provider to reissue the profile.
Installed the eSIM but there is no data after landing	Line switched off, or data still on the primary	Turn on Turn On This Line or Use SIM for the travel plan, then set Cellular Data or Mobile data to it (Step 6). Restart the phone once — a fresh network registration clears most of these.
A large data bill from the first day abroad	Data roaming left on for the primary line	Turn off Data Roaming on the primary line and, on iPhone, Allow Cellular Data Switching (Steps 6 and 7). Ask the carrier whether a retroactive travel pass can be applied to the days already used — many will do it once.
Text-message codes stopped arriving	Primary line off, or blocked by roaming rules	Switch the account to Authenticator notifications or use the rotating six-digit code in the app (Step 4). To receive SMS again, turn the primary line back on — incoming texts are free in most countries even when calls are not.

Related Articles

• How to Use Your Phone as a Wi-Fi Hotspot for Your Laptop
• How to Stay Safe on Public Wi-Fi and Untrusted Networks
• How to Use the Microsoft Authenticator App
• How to Transfer MFA to a New Phone (Microsoft 365)
• How to Secure Your Personal Phone for Work
• How to Set Up Your Work Profile on a Personal Device (BYOD)

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