What is data roaming?
Data roaming is using mobile internet on another operator's network outside your home coverage. The cost depends on your operator's rates, and a travel eSIM still needs data roaming switched on for its own line.
Quick answer
- Data roaming is when your phone uses mobile internet through another operator's network because you are outside your own operator's coverage, usually when you are abroad. Your home operator bills you at its own roaming rates, which can be much higher than a travel SIM or eSIM.
- If you use a travel eSIM, switch data roaming on for the eSIM line only and keep it off for your home SIM, so your home SIM cannot run up roaming charges by accident.
- We do not quote any operator's roaming rates because they differ by operator and by plan, so check with your own operator directly.
What does data roaming mean?
Data roaming is your phone's ability to connect to mobile internet through a network that does not belong to the operator that issued your SIM. The word roaming describes the phone moving onto another network when it leaves your own operator's area.
When you switch your phone on in another country, it looks for available networks, and if your operator has a roaming agreement with a local network, it can connect. If data roaming is switched off, the phone will not use mobile internet over that foreign network.
How does roaming work behind the scenes?
Your home operator signs agreements with partner networks abroad. Your traffic runs over the partner network and is tied back to your home operator, which authenticates you and bills you.
Each operator has different partners in each country, which is why signal quality and rates can differ. Our explainer on roaming partner networks covers this in more detail.
What is the difference between domestic and international roaming?
Domestic roaming means using another operator's network within the same country, for example where your operator has no towers. International roaming means using a network in another country, which is the case behind most high-bill stories.
| Topic | Domestic roaming | International roaming |
|---|---|---|
| Where it happens | Inside the same country | In a country other than your SIM's home country |
| Charges | Depends on the operator and plan | Depends on your operator's roaming rates and plan, so check before you travel |
| What it needs | An agreement between operators within the country | A roaming agreement with a partner network in the destination country |
Domestic roaming compared with international roaming
Is data roaming free?
Not necessarily. Flipping the roaming switch does not cost anything by itself, but data used over a foreign network can be charged at your operator's rates. Some plans include roaming in certain countries, and some do not include it at all.
What happens if data roaming is on when I am abroad?
If your home SIM has roaming on and mobile data enabled, the phone connects through a partner network and your home operator may charge you its roaming rates, which can be very high compared with a travel plan.
Why does roaming cause surprise bills?
The main cause is background data you never asked for: automatic app updates, photo syncing, mail fetching and social app refreshes. All of it counts as billable data while roaming.
Detailed prevention steps are in our guides on avoiding roaming bill shock and on comparing eSIM and roaming costs.
Does a travel eSIM need data roaming on?
Yes, but only for the eSIM line. A travel eSIM connects to local networks in the destination as a visitor, so the phone treats it as roaming, and this option must be on for data to work.
Turning roaming on for the eSIM line does not make your home operator bill you, because the setting is per line, and the eSIM's cost is already fixed in the plan you bought.
- 1Install the eSIM before you travelScan the QR code over Wi-Fi following the eSIM install guide, and give the line an easy label.
- 2Select the eSIM for mobile dataOn iPhone, go to Settings > Cellular > Cellular Data and choose the eSIM line. On Android, go to Settings > Network & internet > SIMs and pick the eSIM for mobile data. Menu names vary by brand and version.
- 3Turn data roaming on for the eSIM onlyEnable the data roaming option on the eSIM line and check that roaming on your home SIM is still off. See the data roaming setup help article for the full steps.
Should I keep roaming off on my home SIM?
Yes. If you use the eSIM as your data line abroad, keep both data roaming and mobile data off on your home SIM, so the phone cannot quietly fall back onto your home SIM's roaming if the eSIM signal drops for a moment.
Keeping data off on the home SIM does not by itself cut you off from your number, but if you need to receive calls or SMS on that SIM abroad, confirm voice and SMS roaming with your operator.
For the basics of the technology, read our guide on what an eSIM is, and for setup, our guide on how to install an eSIM.
FAQ
What is data roaming?+
It is your phone using mobile internet through another operator's network when you are outside your own operator's area, most often abroad. Your home operator does the billing at its own rates.
What is the data roaming meaning in simple terms?+
In simple terms, your phone borrows someone else's network when your own operator's network does not reach. The two operators have an agreement, and you pay through your home operator.
Is data roaming free?+
Not always. The switch costs nothing by itself, but data used on a foreign network can be charged at your operator's rates. Some plans include roaming in certain countries, so check with your operator before you travel.
What happens if data roaming is on while I am abroad?+
If your home SIM has roaming and mobile data on, the phone uses a partner network and your operator may charge roaming rates, including for background app data, which can lead to a surprise bill.
Does a travel eSIM need data roaming on?+
Yes, for the eSIM line only, because the eSIM attaches to local networks as a visitor. Keep roaming off on your home SIM line. The eSIM's cost is already fixed in the plan you bought.
What is the difference between domestic and international roaming?+
Domestic roaming uses another operator's network inside the same country. International roaming uses a network in another country, needs a partner agreement abroad, and is the case that most often leads to high bills.
Instagram and TikTok have no web share button, so we open your phone's share sheet or copy the link instead.