Travel guide
How to Make Sure Your eSIM, Not Your Israeli SIM, Is Handling Data (30-Second Check)
נועה רגב5 min read
On iPhone: go to Settings > Cellular, and check which line has a checkmark under "Cellular Data" - it should be the eSIM, not your Israeli line.
On Android: go to Settings > Network & internet > SIMs, and check which line is set for cellular data.
The check takes less than 30 seconds either way, and it's the difference between smooth browsing on your eSIM and a surprise roaming charge from your Israeli carrier.
Key Takeaways
- The wrong default data line is a quiet, common reason for a "why am I being charged for this" bill - there's no error on screen, you just find out after the fact, on your statement.
- The check itself is short: under 30 seconds on both iPhone and Android, with nothing to install.
- Installing a new eSIM doesn't automatically make it the line that handles data - your phone keeps using the old line unless you manually choose otherwise.
The Check on iPhone
Open Settings > Cellular. Under the "Cellular Data" heading you'll see your two lines, your Israeli line and your travel eSIM, with a checkmark next to whichever one is currently active for data. If the checkmark is next to your Israeli line and not the eSIM, that's exactly the problem: all your browsing is still going through your Israeli line, even if the eSIM is installed and enabled.
- Settings > Cellular.
- Find the checkmark under "Cellular Data" - that's the currently active line.
- If it's not the eSIM, tap "Cellular Data" and select the eSIM line to switch the default to it.
It's worth repeating this check right after landing and again after a connecting flight, because an automatic network reset, for example after a software update, can quietly switch the default back to your Israeli line without you noticing.
By the way, if you're still not sure when to activate your eSIM in the first place, before the flight or only after landing, check out the guide When to Activate Your eSIM: Before the Flight or After Landing? - it directly affects when you should run this check for the first time.
The Check on Android
Open Settings > Network & internet > SIMs (on Samsung and some other devices this may appear as "SIM Manager"). Each line has its own tab. Go into each line and check which one is set as the default for cellular data - that's the line all your traffic actually runs through.
- Settings > Network & internet > SIMs.
- Go into each of the lines shown and check the "Cellular Data" or "Preferred SIM for data" status.
- Make sure the line marked as default is the eSIM, not your Israeli line. If needed, select the eSIM and set it as the default.
Menu names vary slightly between Samsung, Pixel, and Xiaomi, but "SIMs" is the starting point in all cases. If you can't find the setting, search "SIM" directly in the Settings search bar - that's usually fastest.
Not sure your device supports two lines at once? Check SimSIM's list of eSIM-compatible devices before your trip, so you don't find out in the middle of the check.
Why This Happens in the First Place
A phone with two lines, a physical SIM and an eSIM, doesn't automatically choose between them based on location or on what makes sense to you. It keeps using whichever line is set as the default for data, even after you land and even after you install a new eSIM. Installing an eSIM only adds it as an option - it doesn't itself replace the existing default.
If you haven't manually changed the default, your phone will keep browsing through your Israeli line as usual, on roaming, without you noticing, because as far as your regular screen is concerned, the internet just "works."
Neither system, iOS or Android, sends a notification when this happens. Installing an eSIM doesn't remove the need to manually check which line is active for data, per Apple's official guide to managing data lines on Dual SIM and Google's official instructions for managing SIMs on Android.
If you're installing a travel eSIM for the first time, SimSIM's step-by-step installation guide also explains the exact screen where you change the data default.
A common example: a traveler who landed in Budapest, installed an eSIM before the flight but didn't check which line was handling data. A couple of days after returning home, she saw a roaming charge for hundreds of shekels - exactly because her Israeli line had stayed the default, and the eSIM she'd installed never became active.
What to Do If the Wrong Line Is Active
- Switch the data default to the eSIM, following the steps above for your operating system.
- Turn off data roaming on your Israeli line separately, so that even if your phone accidentally switches back to it, you won't be exposed to charges.
The full guide to turning off roaming on your Israeli line, including the second setting that's easy to miss on iPhone, is in the post How to Avoid Roaming Charges From Your Israeli Carrier Abroad.
If after switching the default you're still seeing "No Internet" or weak signal on the eSIM itself, that's a different problem: the eSIM probably wasn't activated correctly, or it isn't registered on the local network. Contact SimSIM's support chat in the app or on the website, with a screenshot of the error, so we can check together whether the eSIM itself is registered properly.
Bottom Line
One short check, and that's all it takes to know for certain which line is costing you money. Do it right after installing a new eSIM, and again after every landing or connecting flight. It's the small habit that prevents the most surprising charge on the list.
Frequently asked questions
After I installed the eSIM, why didn't it automatically become the default data line?
Because the system doesn't change an existing default on its own - it only adds the new line as an additional option. You need to select it manually in your cellular settings, following the steps detailed above.
If I see full signal bars on the network icon, does that mean I'm using the right line?
Not necessarily. The network icon shows signal strength, not which line is actually being used for data. The only way to know for certain is to check directly in settings, as explained above.
Is this check different for a SimSIM travel eSIM versus an eSIM from another provider?
No. The setting that determines which line handles data is a general operating system setting, iOS or Android, not specific to the eSIM provider. The check is the same regardless of provider.