Travel eSIM guide
When do my eSIM days start counting?
The useful answer is simple: your SefereSIM plan days begin when the eSIM first connects to a mobile network at the destination. They do not begin when you buy the plan, receive the QR code, or add the eSIM to your phone.
That gives you time to set it up at home, while you have reliable Wi-Fi and can deal with any small question before travel day.
Installing is not activating
Buying a plan gives you the details needed to add the eSIM. Adding it places that line on your phone. Neither step starts its validity.
The clock starts when the travel eSIM finds and connects to an eligible network in the place covered by the plan. For a country plan, that is normally when you arrive in that country and let the phone use the eSIM. For a regional plan, the same rule applies when the eSIM first connects in a covered destination.
This distinction matters if you buy early. You can purchase a plan days before departure, install it the evening before your flight, and still keep the full plan period for the trip. There is no reason to wait until the airport to add the eSIM.
Set it up before the flight
Do the installation when you are at home or somewhere with dependable Wi-Fi. Keep the QR code or installation details available, then add the eSIM through your phone’s cellular settings. On iPhone, the option is usually under Settings, Cellular, Add eSIM. Android makers use different labels, often under Settings, Network and Internet, SIMs, or Mobile Network.
After the line appears, give it a recognisable label such as "Travel data." This is optional, but it makes the next steps less confusing when your usual SIM is still active.
Check these settings before you leave:
- Keep your home SIM selected for calls and SMS if you want to receive messages and verification codes on that number.
- Set cellular data to the travel eSIM when you are ready to use it abroad.
- Turn on Data Roaming for the travel eSIM. A travel eSIM connects through roaming, so this setting lets the plan reach its network.
- Turn off Data Roaming for your home SIM if you do not want that line to use mobile data overseas.
The wording differs between phones and software versions. What matters is the split: the travel eSIM carries data, while your home SIM remains available for its number.
What to do when you land
After arrival, turn on the travel eSIM if it is not already on and select it for cellular data. Give the phone a minute to register on a network. The first successful connection is the moment the plan begins.
Airport Wi-Fi can hide whether the eSIM is working. Before joining it, check the mobile-data indicator and try a map or a webpage on cellular data. If the phone is still using Wi-Fi, turn Wi-Fi off briefly for the check. Once the eSIM is connected, you can use Wi-Fi as usual when you choose.
A short delay while the phone finds a local network is normal. If it does not connect after a few minutes, check that the eSIM is turned on, it is selected for data, and Data Roaming is enabled for that line.
A quiet preflight check saves time
Install the eSIM before departure, but do not force it to connect to a network outside the plan’s coverage. Download offline maps, save booking details, and keep the QR code or confirmation email somewhere you can reach without data. Then, when the plane lands, you only need to select the travel line for mobile data and let it connect.
Your plan days start with that first network connection at the destination, not with the preparation you did at home.
Keep reading
Internet in the United States: a practical eSIM guide for visitors
Find the plans for your trip
Every destination we sell data for is on one page, at today’s prices in US dollars. The QR code arrives by email, and the service days start counting only when the eSIM first connects at your destination.