The dual SIM eSIM setup is probably the most practical phone configuration for regular international travellers. Your home number stays active - calls and texts come through normally - while your data routes through a cheap local eSIM plan. You get local rates for data without losing your regular number for the people who need to reach you.
How it works
Modern smartphones support running two lines simultaneously: one physical SIM and one eSIM (or two eSIMs on some devices). Each line has independent settings - you can designate one for calls and texts, the other for data.
The typical travel setup: physical SIM (your home carrier) for calls and SMS. eSIM (travel data plan) for mobile data. Your phone bills data charges to the cheap eSIM plan while your home number remains reachable.
Setting it up on iPhone
Install your travel eSIM via Settings then Mobile Data then Add eSIM. Once both lines are active, iOS prompts you to choose defaults:
- Default Voice Line: set to your home physical SIM (so outgoing calls use your home number)
- Mobile Data: set to your travel eSIM (so data routes through the cheap plan)
- iMessage/FaceTime: set to your home SIM (so messages come to your regular number)
Then turn off data roaming on your home SIM: Settings then Mobile Data then Home SIM then Data Roaming then Off. This prevents your phone from accidentally using your home carrier's data while abroad.
Setting it up on Android (Samsung)
Samsung Galaxy phones with a nano-SIM slot and eSIM support - the S20 series and later - can run both simultaneously. Go to Settings then Connections then SIM Manager after installing your eSIM.
In SIM Manager, set voice calls to your home SIM, messages to your home SIM, and mobile data to your travel eSIM. Disable data roaming on the home SIM in its individual settings to avoid accidental charges.
On Pixel phones
Settings then Network and Internet then SIMs. You can set preferred SIM for calls and data separately. The process is similar to Samsung but the menu labels vary slightly.
What about eSIM-only iPhones?
US iPhone 14 and later models have no physical SIM slot. You can run two eSIM lines simultaneously - one set as your primary line (calls/texts), one as your data line. The setup process is the same as above, just both lines are eSIMs rather than one physical and one digital.
The data roaming safety check
After completing the setup, the critical check: make sure your home SIM's data roaming is off. If it's on and your eSIM data drops for any reason, your phone will fall back to the home SIM's data connection - at full roaming rates. Costs can add up fast. Turn it off, and if you ever need to use your home SIM's data as a backup, turn it on consciously.
Common mistakes to avoid
The biggest one: forgetting to switch your data line back to your home SIM when you return from your trip. You land at home, walk out of the airport, and your phone is still routing data through the travel eSIM. If the plan has expired or run out, you'll have no data until you switch back. Quick fix: as soon as you're home, go to settings and set mobile data back to your home SIM.
Another common mistake: leaving iMessage set to the eSIM line. If your iMessage is associated with your travel eSIM number, people who text you via iMessage will send to the wrong number. Make sure iMessage stays linked to your home number or Apple ID email.
Receiving calls abroad with this setup
Your home SIM stays active for incoming calls, but remember - those calls are still being received while your home SIM is roaming. Most carriers charge for receiving calls while roaming, typically $1-3 per minute. For occasional calls this is fine. For long conversations, switch to WhatsApp or FaceTime calls over your eSIM data instead. Data calls are free once you've got the eSIM plan.
Some carriers let you set up WiFi calling, which routes calls over data instead of the cellular network. If your home carrier supports this, turn it on. It means incoming calls route over your eSIM data rather than your home carrier's roaming, saving you the per-minute roaming charges.
Checking it works
Before you leave home, test the setup: enable Airplane Mode, then re-enable only cellular. Open a browser and load a page - check the data activity indicator shows the eSIM carrier name, not your home carrier. Make a call - it should show your home number to the recipient. If both work correctly, you're set.
Browse available travel eSIM plans at getesimonline.com under /countries. The iPhone eSIM guide and Android eSIM guide cover installation in detail if needed.
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