Home SIM plus travel eSIM: how to keep both without surprise roaming

Keeping your home number on while abroad is handy for calls and texts, but one wrong switch lets it use roaming data. Here is the setup that keeps every megabyte on the travel eSIM.

By eSIM Data Deals editorial deskPublished 6 November 2026Updated 6 November 20266 min readSaving data and settings

Short answer

Set the travel eSIM as the line for mobile data, turn off automatic data switching, and turn data roaming off for your home line. Leave roaming on for the travel eSIM. A data-only travel eSIM has no phone number, so calls and SMS still reach your home line. Check your carrier's rates for receiving them abroad.

Why can a home SIM still cost money abroad?

A dual-SIM phone treats each line separately. If the home line is allowed to use data and the phone decides to use it, even for a moment, that data is charged at your home carrier's roaming rate. The usual causes are simple: the wrong line chosen for data, automatic data switching left on, or data roaming left on for the home line.

The travel eSIM is a separate, data-only line. TripoSIM, for example, says its eSIMs provide mobile data only, have no phone number, and leave your regular SIM active for calls and SMS.

What is the safe setup, step by step?

Label both lines. Name them clearly, for example Home and Travel, so every menu shows which is which.
Choose the travel eSIM for mobile data. iPhone: Settings, Cellular, Cellular Data, choose the travel line. Pixel: Settings, Network & internet, SIMs, choose the SIM for mobile data.
Turn off automatic data switching. iPhone: turn off Allow Cellular Data Switching. Android: turn off any automatic or smart data switching between SIMs.
Turn data roaming off for the home line. Select the home line and switch Data Roaming off, so it cannot use roaming data even by accident.
Turn data roaming on for the travel eSIM. Travel eSIMs often connect through partner networks and need roaming on for their own line.
Decide what the home line does for calls and SMS. Keep it on to receive calls and texts, and check your home carrier's roaming rates for them.
Check the home line's data counter after day one. It should show no mobile data used abroad. If it shows any, look again at steps 2 to 4.

The setup this guide recommends.
Setting	Home line	Travel eSIM
Line is on	Yes, for calls and SMS	Yes
Used for mobile data	No	Yes
Data roaming	Off	On (usually needed)
Automatic data switching	Off (phone-wide)	Off (phone-wide)
Phone number	Your normal number	None: data only

Where are the switches on iPhone?

Data line: Settings → Cellular → Cellular Data, then choose the travel line. On the same screen, turn off Allow Cellular Data Switching.
Roaming per line: Settings → Cellular, tap the home line, then Cellular Data Options (or the line's own settings) and turn Data Roaming off. Do the same for the travel line and turn it on.
Default voice line: keep your home number as the default for calls and iMessage if you want people to reach you as usual.

Apple explains that with Allow Cellular Data Switching on, the data line switches automatically for the length of a call on your other line, and that this switching doesn't work while you are using data roaming. Abroad, most travellers are better off with it off, so data never has a route onto the home line.

Where are the switches on Android?

Pixel: Settings → Network & internet → SIMs. Choose the travel eSIM for mobile data, then open the home SIM and turn Roaming off.
Samsung: Settings → Connections → SIM manager. Set Mobile data to the travel eSIM and turn off Auto data switching if it is shown.
Other makers use similar names: look for the preferred SIM for data, and any "smart" or "automatic" data switching.

What about calls, SMS and one-time codes?

With the home line on, texts and calls to your normal number still reach you, if your carrier has roaming in that country. That matters for things like one-time sign-in codes sent by SMS. Points to check before you go:

Your carrier's roaming rates for receiving calls, receiving texts and sending texts. Some carriers charge for these and some don't.
Wi-Fi Calling on the home line, if your carrier supports it abroad. It can carry calls over Wi-Fi or over the travel eSIM's data. Ask your carrier how it is charged.
Voicemail. Some carriers charge to forward calls to voicemail while roaming. Your carrier's roaming page will say.
App calling. WhatsApp, FaceTime and similar apps call over the travel eSIM's data. Count them in your data budget: video calls are among the heaviest things you can do.

What should I do before the flight?

Install the travel eSIM at home on Wi-Fi. TripoSIM says its plans start when the eSIM first connects at your destination, and recommends keeping the eSIM's line switched off until you arrive.
Label the lines and set the switches above while you are still at home, so nothing changes in a rush at arrivals.
Reset the data statistics so you can read clean numbers on day one.

How do I know it worked?

After the first day abroad, read the data counter for each line. On iPhone, the Cellular screen shows usage for the selected data line, and the line choice is visible at the top. The home line should show no mobile data used since you landed. On Pixel, check each SIM under Settings → Network & internet → SIMs. If the home line shows data, go back over steps 2 to 4. For a deeper look at background data on dual SIM, see dual-SIM data controls.

What about the trip home?

Back home, switch mobile data back to the home line, turn the travel eSIM's line off, and leave it installed until its plan has expired in case you need it again. Turning roaming back on for the home line is only needed if your home plan uses it.

What about iMessage, FaceTime and WhatsApp with two lines?

Messaging apps tied to your phone number keep working over the travel eSIM's data. iMessage and FaceTime use your home number as the identity and send data over whichever line carries mobile data, so with the setup above they use the travel eSIM. WhatsApp is tied to the number you registered with, not to the line carrying data, so it keeps working as normal. Don't re-register it with a new number abroad. A data-only travel eSIM has no number to register anyway. Audio and video calls in these apps are counted as travel data, so include them in your budget. Video calls are among the heaviest things a phone does, at roughly 0.5–1 GB an hour for a 1:1 call, depending on quality.

Frequently asked questions

Will I still get texts on my home number with a travel eSIM?

Usually yes, if the home line stays switched on and your carrier supports roaming where you are. The travel eSIM is data only and has no number, so SMS keeps arriving on the home line. Some carriers charge for texts or calls received abroad, so check their roaming rates.

Do I need data roaming on for a travel eSIM?

Often yes, for the travel line. Many travel eSIMs connect through partner networks, which the phone treats as roaming. Turn data roaming on for the travel eSIM only, and keep it off for the home line.

What is Allow Cellular Data Switching on iPhone?

It lets the iPhone use the other line's data, for example during a call on that line. Abroad it could put data on your home line. Apple notes the switching doesn't work while you are using data roaming, but turning it off removes the doubt.

Does a data-only eSIM give me a local phone number?

No. A data-only travel eSIM, such as TripoSIM's, has no phone number of its own. Calls and texts stay on your home number, and you can call over data with apps such as WhatsApp or FaceTime.

Sources and how we checked

Figures were read from these pages on 6 November 2026. Apps change their settings and rates; if a number here disagrees with the app on your phone, trust your phone's own data counter. See how we get our figures.