Do I Need to Turn Off My Primary SIM When Using eSIM?

Q: Can I receive SMS for banking or 2FA while using eSIM?

Yes. As long as your primary SIM remains active, you can receive SMS for banking, verification codes, and other services.

Q: Will I be charged roaming fees if my primary SIM is on?

Not if data roaming is turned off on the primary SIM. Charges usually apply only when mobile data is used.

Q: Can I turn my primary SIM back on anytime?

Yes. You can turn your primary SIM on or off at any time from your phone settings.

Short answer: No, you usually don’t need to turn off your primary SIM when using a travel eSIM.
In fact, keeping your main SIM active is often the best setup, as long as it’s configured correctly.

In this guide you’ll learn:

When you should keep your primary SIM ON
When it’s better to turn it OFF
How to avoid roaming charges completely
The safest setup for travel.

The recommended setup for most travelers

For most people using a data-only travel eSIM, the best configuration is:

Primary SIM → Calls & SMS
Travel eSIM → Mobile data
Data roaming OFF on the primary SIM
Data roaming ON on the travel eSIM (if required)

This way:

You keep your phone number active
Apps like WhatsApp keep working normally,
You avoid any unexpected roaming fees.
If you’re not sure how Dual SIM works, read this first: 👉 https://novesim.com/esim-and-physical-sim-dual-sim/

When you should NOT turn off your primary SIM

Keep your primary SIM ON if:

You want to receive SMS (bank codes, 2FA, confirmations)
You want to receive calls on your usual number
You use WhatsApp, Viber, Telegram with your main number
Your carrier does not charge for incoming SMS abroad

In most cases, turning off data roaming on the primary SIM is enough.

When turning off your primary SIM makes sense

You may want to turn OFF your primary SIM if:

Your carrier charges for incoming SMS abroad
You want zero risk of roaming charges
You don’t need calls or SMS during the trip
You’re using only internet-based apps

Even then, it’s optional — not required.

How to avoid roaming charges 100%

Do this checklist once before traveling:

1. Install your travel eSIM 👉https://novesim.com/how-to-install-esim-on-samsung/
2. Set Mobile Data = Travel eSIM
3. Turn Data Roaming OFF on your primary SIM
4. Turn Data Roaming ON for the travel eSIM (if needed)
5. Set your primary SIM as Calls/SMS only (Optional)

This setup is safe and used by most frequent travelers.

iPhone: recommended settings

Settings → Cellular
Cellular Data → Travel eSIM
Default Voice Line → Primary SIM
Data Roaming
- Primary SIM → OFF
- Travel eSIM → ON (if required)

Android / Samsung: recommended settings

Settings → Connections → SIM Manager
Mobile Data → Travel eSIM
Calls & Messages → Primary SIM
Data Roaming
- Primary SIM → OFF
- Travel eSIM → ON (if required)

If switching SIMs is unclear, read: 👉 https://novesim.com/switch-between-esim-and-physical-sim/

Common misconceptions

“I must turn off my main SIM or eSIM won’t work -> ❌ False. Dual SIM phones are designed to handle both lines simultaneously.
“WhatsApp will stop working” -> ❌ False. WhatsApp uses your number, not your SIM, and works through internet.
“Turning off the primary SIM saves battery” -> ⚠️ Slightly, but the difference is usually minimal.

Travel without roaming stress. Choose a plan for your destination here: 👉 https://novesim.com/destinations/

Frequently asked questions

Do I need to turn off my main SIM when using eSIM?

No. Most travelers keep their primary SIM active for calls and SMS and use the eSIM only for mobile data.

Can I receive SMS for banking or 2FA while using eSIM?

Yes, as long as your primary SIM remains active in the phone.

Will I be charged roaming fees if my primary SIM is on?

Not if data roaming is OFF. Charges usually apply only when mobile data is used.

Can I turn my primary SIM back on anytime?

Yes. You can turn it on or off instantly in your phone settings.