¿Cómo sabe el móvil por dónde enrutar cada cosa?

El sistema operativo tiene una capa de gestión Dual SIM que asigna roles a cada línea. Puedes configurar: En iOS (iPhone), esto se gestiona desde Ajustes → Datos móviles y desde Ajustes → Teléfono. En Android, la ruta varía según el fabricante, pero suele estar en Ajustes → Conexiones → Administrador de SIM.

¿Listo para viajar con eSIM?

Activa tu eSIM en minutos y viaja sin roaming. Tu número habitual siempre disponible.

¿Puedo usar eSIM y SIM física al mismo tiempo en cualquier móvil?

No en todos. Necesitas un móvil con soporte Dual SIM + eSIM. La mayoría de iPhones desde el XS (2018), los Samsung Galaxy S21 en adelante y muchos Pixel lo soportan. Consulta las especificaciones de tu modelo en la web del fabricante antes de activar una eSIM.

¿Pierdo mi número al activar una eSIM?

No. La eSIM es una línea adicional o de sustitución que no afecta al número de tu SIM física. Puedes conservar tu número habitual en la SIM física y usar la eSIM para datos o una segunda línea sin ningún riesgo para tu número actual.

¿Puedo tener datos activos en las dos SIMs a la vez?

En la mayoría de los dispositivos solo puedes tener datos activos en una SIM al mismo tiempo, aunque puedes cambiar cuál los usa en cualquier momento desde los ajustes. Algunos modelos Android permiten alternar automáticamente según la señal disponible.

¿Qué pasa con las llamadas y los SMS en Dual SIM + eSIM?

Puedes recibir llamadas y SMS en ambas líneas simultáneamente. Las dos están activas y atentas. Para las llamadas y SMS salientes tendrás que elegir una línea predeterminada, aunque puedes cambiar en cualquier momento al hacer una llamada.

¿La eSIM de viaje funciona como segunda línea sin tocar mi SIM física?

Exactamente. Una eSIM de viaje como las de PuraSim se instala como segunda línea directamente en el chip eSIM de tu móvil. Tu SIM física permanece intacta con tu número local, y la eSIM te da datos locales en el destino sin roaming, sin cambiar tarjetas y sin costes adicionales en tu línea habitual.

¿Pueden funcionar la eSIM y la SIM física a la vez para llamadas y datos?

Sí, funcionan simultáneamente: las dos líneas están operativas al mismo tiempo para recibir llamadas y SMS. La única limitación real está en los datos móviles, que en la mayoría de terminales solo pueden ir por una línea a la vez, aunque puedes cambiar cuál en cualquier momento desde los ajustes.

¿La eSIM y la SIM física dan 5G a la vez?

Normalmente no las dos a la vez. En la mayoría de móviles Dual SIM + eSIM, el 5G solo está disponible en la línea que tienes configurada como línea de datos activa; la otra línea se queda en 4G/VoLTE para llamadas y SMS mientras tanto. No es un fallo del teléfono, es cómo gestionan la radio la mayoría de los chips Dual SIM actuales.

eSIM and physical SIM at the same time: how dual SIM works

In short: Yes, you can have an active eSIM and physical SIM at the same time—that's how dual SIM with eSIM works—on any compatible device. Your usual number stays on the physical SIM, and the eSIM acts as a second line, ideal for local data when traveling without paying for roaming or changing cards.

Can you have an eSIM and physical SIM at the same time?

The short answer is yes. Dual SIM with eSIM technology allows your mobile to manage two lines simultaneously: one in the physical slot (the usual SIM card) and another in the eSIM chip integrated into the device itself.

The key is the word simultaneous. It's not about switching between one and the other by turning off the one you're not using: both lines are active at the same time, receiving calls and messages, each with its own number. What is limited on most devices is mobile data usage, which can generally only go through one line at a time (although you decide this from the settings).

For this to work, your device needs to meet two conditions:

Have eSIM support (eSIM chip integrated into the motherboard)
Be Dual SIM, meaning capable of managing two active lines

If you want to better understand what an eSIM is exactly before continuing, we recommend reading our article on what a virtual eSIM is and how it works.

Aspect	Physical SIM	eSIM
Installation	Insert physical card into tray	Scan a QR code or install with a link, no card needed
If you lose or break your phone	Retrieve the card and insert it into another device	It is linked to the device; to retrieve it, you need to reinstall it from your account with the operator that issued it, if allowed
Operator change	Must request a new card or wait for delivery	Instant installation, no waiting or shipping
International travel use	Roaming from Spanish operator, high cost outside the EU	Local data at destination price, no roaming
Number of stored lines	One per physical card, changed manually	Several eSIMs stored on the same chip (limit depends on model)

How Dual SIM with eSIM works

The technical operation is simpler than it seems. Your mobile has two network "slots": the physical (where you insert the card) and the virtual (the eSIM chip). The operating system treats them as two independent lines, each with its own phone number, operator, and data plan.

What can each line do?

Calls: You can receive calls on both lines simultaneously. When someone calls your physical number while you're talking on the eSIM, you'll receive a notification (depending on the device).
SMS: Both lines receive text messages independently.
Mobile data: Usually, only one line can use mobile data at a time. You choose which one, and you can switch at any time.

How does the mobile know where to route everything?

The operating system has a Dual SIM management layer that assigns roles to each line. You can configure:

Default data line
Line for outgoing calls
Line for outgoing SMS

On iOS (iPhone), this is managed from Settings → Mobile Data and from Settings → Phone. On Android, the path varies by manufacturer, but it is usually in Settings → Connections → SIM Manager.

What about 5G? eSIM and physical SIM working simultaneously on 5G networks

This is where many people are surprised. Just because your mobile is compatible with 5G and with Dual SIM + eSIM doesn't mean that both lines will simultaneously browse on 5G. On most devices with DSDS (Dual SIM Dual Standby, which is how almost all current Dual SIM + eSIM devices work), 5G is only available on the line you have marked as the data line at that moment. The second line—the one you only use for calls and SMS—usually stays on 4G/VoLTE in the meantime, and that's normal, not a phone fault.

If you change the default data line, 5G "travels" with it: the new line gets 5G and the other drops to 4G. This is not an eSIM issue per se, but rather how most Dual SIM mobile radio chips on the market are managed. If you need maximum speed at your destination, make sure you have set the travel eSIM as the active data line, not just that you have it installed.

If you have an iPhone and want to see the complete eSIM installation process, check out our step-by-step guide to installing an eSIM.

Most common use cases (travel + work)

The eSIM + physical SIM combination is especially powerful in two scenarios that are constantly repeated among our users:

1. Frequent traveler who wants to keep their local number

This is the most common case. You travel to Europe, Asia, or America and need cheap local data, but you can't deactivate your Spanish line because your clients, family, or bank call you on that number.

The solution: you keep your physical SIM with your usual number (in voice/SMS only mode or with roaming deactivated to avoid costs) and activate a local data eSIM like PuraSim's. Result: fast and cheap data at your destination, and your number always available to receive important calls.

Check out our eSIMs for Europe if you're traveling to the continent or visit our eSIM for travel page to find the plan that best suits your destination.

2. Separation of professional / personal life

More and more people are using Dual SIM to have their work number and personal number on the same device. With eSIM + physical SIM, you can:

Use the physical SIM for the personal number (usual contract operator)
Use the eSIM for the work line (virtual operator or corporate eSIM)
Mute the work line outside of work hours without turning off the phone

3. Rate optimization in areas with unequal coverage

If your main operator has poor coverage in certain areas (rural, basements, specific buildings), you can have a second line from a different operator as an eSIM. The mobile does not automatically switch between operators for data, but you can manually change in seconds without touching physical cards.

How to configure which SIM uses data and which uses calls

The configuration varies between iOS and Android, but the concept is the same: assign roles to each line.

On iPhone (iOS)

Go to Settings → Mobile Data
You will see both lines listed. Tap the one you want to use data
For calls: Settings → Phone → Default Line
For iMessage and FaceTime: Settings → Messages → Send & Receive

iPhone also offers the option to "Allow Mobile Data Switching" which automatically switches to the other line if the current one has a poor signal. It's in Settings → Mobile Data → Mobile Data.

On Android (Samsung, Pixel, etc.)

Go to Settings → Connections → SIM Manager (on Samsung) or Settings → Network & internet → SIMs (on Pixel)
Select the default line for data, calls, and SMS separately
Some models allow activating "adaptive data" which automatically switches

Practical tip for travelers

Before you travel, set your travel eSIM as the default data line and your physical SIM as the call line. This way, your phone will automatically use local eSIM data and you'll continue to receive calls on your usual number without roaming charges.

To better understand the difference between the physical and virtual chip before making a decision, visit our guide on international physical chip vs eSIM.

Models that support Dual SIM + eSIM

Not all eSIM-enabled phones are Dual SIM. Here are the most popular models confirmed with full simultaneous eSIM + physical SIM support:

Apple iPhone

iPhone XS, XS Max, XR (2018) — first with Dual SIM + eSIM
iPhone 11, 12, 13, 14 — all models (except US eSIM-only versions)
iPhone 15 and 16 — all international models (US models are eSIM-only with no physical slot)

Important note: iPhones sold in the US from the 14 onwards do not have a physical SIM slot. They are eSIM-only with the possibility of storing up to 8 eSIMs.

Samsung Galaxy

Galaxy S21, S22, S23, S24 and variants (Ultra, Plus, FE)
Galaxy Z Fold 3, 4, 5, 6
Galaxy Z Flip 3, 4, 5, 6
Galaxy A54, A55 (mid-range with eSIM)

Google Pixel

Pixel 3 and later with Dual SIM + eSIM support
Pixel 6, 7, 8, 9 — all compatible

Other manufacturers

Motorola: Razr 2022 and later, recent Edge series
Oppo / OnePlus: Find X models and OnePlus 12 onwards (selected markets)
Xiaomi: 13 Pro, 14 Ultra (international markets)

Important: Some mobile phones sold in specific markets or unlocked for specific operators may have the eSIM function deactivated at the software level. Always check the official manufacturer's specifications for your region.

Common myths and errors when using eSIM and physical SIM together

This is what almost no one tells you before setting up both lines, and what often leads to doubts or a surprise on your bill:

"If I have both active, I'll go faster because I'm combining data from both."

It doesn't work that way. Mobile data goes through only one line at a time on the vast majority of devices; having the second line active doesn't add speed or bandwidth. The only thing you achieve by combining two lines is switching from one to the other as needed, not using them in parallel for browsing.

"If I deactivate general roaming, I won't be charged anything for the physical SIM anymore."

This is the error that causes the most surprise bills. Deactivating the general data roaming switch is not always enough: some mobile phones still allow verification SMS, visual voicemail, or occasional connection attempts from the physical SIM to pass through if you don't also check the data roaming for that specific line, not just the "active data line" selector. If you want to understand where that unexpected charge comes from, read our guide on what data roaming is before you travel.

"My WhatsApp or my bank will stop working if the line using data is no longer the physical one."

No, and this is one of the most common doubts. Apps that verify your number (WhatsApp, banking, 2FA via SMS) are still tied to your physical SIM number even if data goes through the eSIM. You receive the verification SMS just the same, because both lines are active for calls and messages; only where you browse changes.

"Any travel eSIM can be installed on any Dual SIM mobile."

Almost, but not entirely. Some models only allow one eSIM to be active at a time even if they support several stored, and a few operator-locked devices restrict the installation of eSIMs from other providers. Before buying, check in settings that your model appears as eSIM compatible and that it is unlocked.

When NOT to buy a travel eSIM

And here we must be honest: if you are going to spend a weekend in a European Union country, your Spanish contract rate usually already includes data roaming at no extra cost within the EU — you don't need to buy anything. Where it does make sense to activate an eSIM before leaving is outside the EU, where your Spanish operator's roaming charges skyrocket in a matter of minutes: for example, for a trip to the United States, activating the eSIM for the United States before landing and leaving the physical SIM only for calls and SMS will save you that surprise. If you have doubts about when one option is better than the other, our comparison of eSIM vs roaming breaks it down in more detail.

Conclusion

The combination of eSIM and physical SIM simultaneously is one of the most practical features of modern mobile phones, and it's available to any user with a compatible device since 2018. You don't lose your number, you don't have to choose between one and the other, and you gain enormous flexibility in managing data, calls, and costs.

The most powerful use case is international travel: keep your physical SIM with your usual number so you don't miss any important calls, and activate a local data eSIM to browse without limits and without surprise roaming bills.

Ready to travel with eSIM?

Activate your eSIM in minutes and travel without roaming. Your usual number always available.

See eSIMs for Europe eSIM for travel

Frequently asked questions about eSIM and physical SIM simultaneously

Can I use eSIM and physical SIM at the same time on any mobile?

Not on all. You need a mobile with Dual SIM + eSIM support. Most iPhones from XS (2018), Samsung Galaxy S21 onwards, and many Pixels support it. Check your model's specifications on the manufacturer's website before activating an eSIM.

Do I lose my number when I activate an eSIM?

No. The eSIM is an additional or replacement line that does not affect your physical SIM number. You can keep your usual number on the physical SIM and use the eSIM for data or a second line without any risk to your current number.

Can I have active data on both SIMs at the same time?

On most devices, you can only have active data on one SIM at a time, although you can switch which one uses it at any time from the settings. Some Android models allow automatic switching based on available signal.

What about calls and SMS on Dual SIM + eSIM?

You can receive calls and SMS on both lines simultaneously. Both are active and ready. For outgoing calls and SMS, you will need to choose a default line, although you can switch at any time when making a call.

Does the travel eSIM work as a second line without touching my physical SIM?

Exactly. A travel eSIM like those from PuraSim is installed as a second line directly onto your phone's eSIM chip. Your physical SIM remains intact with your local number, and the eSIM gives you local data at your destination without roaming, without changing cards, and without additional costs on your usual line.

Can the eSIM and physical SIM work simultaneously for calls and data?

Yes, they work simultaneously: both lines are operational at the same time for receiving calls and SMS. The only real limitation is mobile data, which on most devices can only run on one line at a time, although you can switch which one at any time from the settings.

Do the eSIM and physical SIM both provide 5G simultaneously?

Normally not both at once. On most Dual SIM + eSIM phones, 5G is only available on the line you have set as the active data line; the other line remains on 4G/VoLTE for calls and SMS in the meantime. This is not a phone malfunction; it's how most current Dual SIM chips manage the radio.

Written by Marc González Sáez Founder of PuraSim and a specialist in eSIM and connectivity for travelers. He has been helping people travel connected worldwide for years without overpaying for roaming, and personally tests eSIMs in each destination before recommending them.