Data Roaming On or Off with a Travel eSIM? Set Each Line Right

You land, switch your phone back on, and it shows two lines with two roaming switches. One of them should be on. The other should usually be off. Mixing them up is one of the most common reasons a new travel eSIM shows no internet, and one of the easiest ways to get a roaming bill from home.

Short answer

Set each line separately:

• Travel eSIM: data roaming on. For an ElloSim eSIM this is required to connect abroad, and the ElloSim FAQ says it does not cost anything extra.
• Home line: data roaming off, so it cannot use mobile data abroad.
• Mobile data: choose the travel eSIM, and turn off automatic data switching.

One important limit: turning off data roaming on your home line only covers data. Calls and texts on your home number can still be charged by your home provider, so check their rates before you go.

Why the travel eSIM needs roaming on

A travel eSIM connects to networks in your destination as a visitor. Your phone sees that as roaming, even though you paid for the data in advance.

So if the roaming switch on the travel line is off, the phone will not use it for data. You might see a network name and signal bars, and still have no internet.

For an ElloSim eSIM, the data you use comes from the plan you bought. The roaming switch is simply what lets the line connect. If you use another provider, check its own guide, because setups can differ.

Two lines, two jobs

Here is how the settings usually look on a dual-SIM phone during a trip:

ElloSim eSIMs are data-only unless a plan page says otherwise, so your home line stays in charge of your phone number.

Pick the data line, then stop it switching

Choosing the data line matters as much as the roaming switches.

iPhone: go to Settings, then Cellular (or Mobile Service), then Cellular Data, and choose the travel line. Apple notes that when you keep both lines on, the travel eSIM is used for data, but you may still face roaming charges on your home line. See Apple's travel eSIM guide.

Then look for Allow Cellular Data Switching. Apple explains that this lets the iPhone use data from both plans, depending on coverage. See Apple's Dual SIM guide. For most trips, turn it off.

Google Pixel: go to Settings, then Network & internet, then SIMs. Google lets you choose one default SIM for mobile data, and you can turn off Automatic data switching there. See Google's dual SIM help.

Samsung Galaxy: go to Settings, then Connections, then SIM manager, and set Mobile data to the travel line. Menu names vary by model.

Why switching matters: say your train leaves the city and the travel line drops to one bar. With switching on, your phone may move data to whichever line has coverage. With it off, data waits for the travel line. It might be slower for a minute, but it stays on the plan you paid for.

What home data roaming off does not stop

Turning data roaming off on your home line stops that line using mobile data abroad. It does not make the line free.

Depending on your home plan, you might still pay for:

• Calls you answer or make on your home number
• Texts you send, and sometimes texts you receive
• Voicemail, if your provider charges for it abroad

Your home provider sets these rates, not your travel eSIM. Before you fly, check their roaming page or app, or ask them directly.

If you do not need your number at all on the trip, you can turn the home line off completely. Just remember that bank codes sent by text will not reach you. Our guide to bank verification texts abroad explains the options. If you mainly want to keep chatting, see keeping your WhatsApp number.

Some people also turn on Wi-Fi Calling for their home line, if their provider offers it. Ask your provider whether calls that way are included in your plan before relying on it.

When to set each switch

The order matters a little:

1. At home, on Wi-Fi: install the travel eSIM. If your plan starts on first connection, keep the travel line off until you land. Our guide on when to activate a travel eSIM explains the timing.
2. Before you board: turn data roaming off on your home line. That way it cannot pick up data the moment you land.
3. After you land: switch the travel line on, turn its data roaming on, and select it for mobile data.

Crossing borders by road or rail? The same settings work, but check that each country on your route is covered. Our Europe route checklist walks through it, and the Japan eSIM guide covers the same checks for Japan.

A one-minute check after landing

1. Turn Wi-Fi off, so you are testing mobile data.
2. Confirm the travel line is on, with data roaming on.
3. Confirm the travel line is selected for mobile data.
4. Open a web page you have not opened before.

If it loads, you are set. If it does not, work through our no-internet checklist before changing anything else, and keep the eSIM installed.

FAQs

Does turning on data roaming for my travel eSIM cost extra?

For ElloSim eSIMs, our FAQ says no. Your data comes from the plan you bought. For other providers, check their terms.

If home data roaming is off, can my home provider still charge me?

Yes, it can. Data roaming off covers mobile data only. Calls and texts on your home number can still be charged, depending on your home plan.

Can I keep both lines switched on?

Yes, on a dual-SIM phone. Choose the travel eSIM for mobile data, keep roaming off on your home line, and keep your home line as the default for calls and texts.

Should automatic data switching be on or off?

For most trips, off. That keeps your data on the travel eSIM instead of moving to your home line when coverage changes.