The combination of Dual SIM with eSIM is one of the smartest uses of eSIM technology for travelers: you keep your Spanish number active while using cheap data abroad with the eSIM. Here's how to configure it correctly to get the most out of it.
What is Dual SIM with eSIM
Dual SIM with eSIM means having two active lines simultaneously on the same device:
- Line 1 (physical SIM): your usual Spanish SIM — for calls and SMS from your regular number
- Line 2 (eSIM): the PuraSIM data plan — for cheap internet at your destination
| Aspect | Physical SIM (your Spanish operator) | Travel eSIM (PuraSIM) |
|---|---|---|
| Main function | Calls + SMS + emergency data | Main mobile data |
| Data cost | Expensive roaming outside EU | Local price (affordable) |
| Phone number | Your usual Spanish number | No number or temporary number |
| WhatsApp/Telegram | ✅ Your main account | Data only (no number) |
| Activation | Always active | Activate upon arrival at destination |
How it works in practice
With the correct Dual SIM configuration, when someone calls your Spanish number:
- The call reaches your Spanish SIM (with your operator's reception costs, generally free in the EU and low in other countries)
- You answer normally, your number doesn't change
- Meanwhile, internet data (WhatsApp, Google Maps, browsing) goes through the PuraSIM eSIM
Optimal Configuration
On iPhone
- Install the PuraSIM eSIM (Settings → Mobile Data → Add Data Plan)
- Mobile Data: Settings → Mobile Data → "Mobile Data" → select the eSIM line
- Calls: "Default Voice Line" → Spanish SIM
- iMessage/FaceTime: Settings → Messages/FaceTime → select Spanish SIM
- Roaming: Activate "Data Roaming" only for the eSIM line
On Android/Samsung
- Install the PuraSIM eSIM (Settings → Connections → SIM Manager)
- Under "Preferred SIM for data" select the eSIM
- Under "Preferred SIM for calls" select the Spanish SIM
- Activate data roaming for the eSIM
Real Savings with Dual SIM
| Scenario | With operator roaming | With Dual SIM eSIM | Savings |
|---|---|---|---|
| 10-day Europe vacation (10 GB) | €35–55 | €8.90 | €26–46 |
| 7-day US business trip (8 GB) | €60–120 | €12.50 | €47–107 |
| 15-day LatAm trip (12 GB) | €80–180 | €14.90 | €65–165 |
| 1-month Asia nomad (20 GB) | €150–300 | €22 | €128–278 |
Limitations of Dual SIM with eSIM
- Calls over data: If you receive a call on the Spanish SIM while using eSIM data, in some cases the device may momentarily pause data during the call (depends on the model)
- WhatsApp: WhatsApp is linked to a number; you cannot have two WhatsApp accounts on the same installation without additional apps
- Battery consumption: Having two active lines consumes slightly more battery (+3–7%)
Conclusion
Dual SIM with eSIM is the optimal strategy for the modern traveler: you maintain your digital identity (Spanish number, WhatsApp) and pay local prices for data. Savings on a 10-day trip outside the EU can exceed €60.
Frequently asked questions
Can I receive SMS from my bank in Spain while using the travel eSIM?
Yes. Bank SMS go to your Spanish SIM, which remains active. You will only pay the cost of receiving SMS in roaming from your Spanish operator (generally free in the EU, low outside).
Does WhatsApp still work with my Spanish number with Dual SIM?
Yes. WhatsApp is linked to your physical SIM number. You can use it normally using the travel eSIM data.
Can I activate the eSIM when I arrive at my destination or do I have to do it before?
You can do it before your trip (recommended) or upon arrival with airport WiFi. If you install it beforehand, you only need to activate the line when you land.
Can the travel eSIM also receive calls?
It depends on the plan. Most travel eSIMs are data-only. For calls, you need an eSIM with an included number, which are more expensive and less common.
Does Dual SIM work on all iPhones?
From iPhone XS/XR onwards. US iPhone 14/15/16 models only have eSIM (no physical SIM), so 'Dual SIM' means two eSIMs.
