Can I Use an eSIM without Removing My Old SIM Card?

You can usually use an eSIM without removing your old SIM card when the phone supports Dual SIM and is unlocked. The physical SIM can keep your usual number, while the travel eSIM supplies mobile data abroad.

The two lines have separate roles. Installing an eSIM does not copy, replace or cancel the number on the old SIM, but you must choose which line handles mobile data and control roaming on each line.

NoveSIM travel eSIMs are data-only. We do not provide a local telephone number or conventional calls and SMS. Your old SIM can remain available for those services, subject to its carrier’s roaming charges and coverage.

Quick answer: Keep the old SIM installed, add the travel eSIM and label the lines clearly. Select the NoveSIM eSIM for Mobile Data, enable Data Roaming on that travel line, keep Data Roaming off on the old SIM and disable automatic data switching when avoiding home-carrier data charges.

Can a Physical SIM and an eSIM Work Together?

Yes, on a compatible Dual SIM phone. Many devices support one physical SIM plus one active eSIM. Some newer models can keep two eSIMs active instead, while other regional variants have different limitations. Check the exact model rather than relying only on the phone’s family name.

Apple states that an iPhone can use only one mobile-data network at a time. Google similarly allows the user to assign calls, messages and data to different lines on supported Pixel devices. The precise combination of active SIMs depends on the device, software and carrier support.

Confirm the handset through the NoveSIM-compatible device list. If the menus are unclear, use the guide to check whether a phone supports eSIM.

Will the eSIM Replace My Existing Number?

No. Adding a travel eSIM does not change the number attached to the physical SIM. Your primary carrier continues to control that number, its calls, ordinary SMS, voicemail and roaming charges.

Internet services such as WhatsApp can use the NoveSIM data connection while retaining the account number already registered in the app. Do not choose a prompt to change the WhatsApp number merely because you added a data-only eSIM. Read more about how to keep your number with a data eSIM.

Recommended Dual SIM Setup for Travel

Setting	Recommended starting point	Reason
Mobile Data	NoveSIM travel eSIM	Routes internet traffic through the travel plan
Data Roaming on travel eSIM	On	Allows the plan to connect to its supported partner network
Data Roaming on old SIM	Off	Reduces the risk of home-carrier data roaming
Automatic data switching	Off	Prevents the phone from silently moving data to the old SIM
Default voice line	Old SIM, if needed	Keeps ordinary calls on the number-owning line
Network selection	Automatic	Lets each line register with an authorised network

These settings protect mobile data, not every possible roaming charge. The old carrier may still charge for outgoing or answered calls, voicemail, SMS or Wi-Fi Calling according to its tariff.

How to Set the Lines on an iPhone

Open Settings → Mobile Service or Cellular.
Confirm that both lines appear and give them clear labels such as Primary and Travel.
Open Mobile Data or Cellular Data and select the NoveSIM eSIM.
Turn off Allow Mobile Data Switching when you do not want the phone to use the old SIM for data.
Open the NoveSIM line and enable Data Roaming.
Open the primary line and keep its Data Roaming off.
Choose the old SIM as the default voice line if you intend to retain it for calls and ordinary SMS.

If the travel profile is not yet installed, follow the iPhone eSIM installation guide on dependable private Wi-Fi.

How to Set the Lines on an Android Phone

Menu names vary. On Pixel, look under Settings → Network & Internet → SIMs. On Galaxy, use Settings → Connections → SIM Manager.

Confirm that the physical SIM and travel eSIM are both listed.
Enable the travel eSIM and select it as the preferred SIM for Mobile Data.
Enable Data Roaming for the travel eSIM.
Keep roaming disabled for the old SIM.
Disable automatic or backup data switching if the phone offers it.
Leave network selection on Automatic unless NoveSIM Support gives another instruction.

Galaxy users can follow the dedicated guide for choosing the data SIM on Samsung. For other supported Android devices, use the Android eSIM installation guide.

Can the Old SIM Still Receive SMS and OTP Codes?

It may remain able to receive ordinary SMS while enabled and registered on a network, but this depends on the home carrier, destination coverage and roaming agreement. Receiving an SMS is often free, but that is not universal; check the carrier’s current tariff.

Some banks and services also restrict verification while abroad or use app-based approval instead. Before departure, confirm access to essential accounts, save recovery methods and do not rely on a single SMS route for urgent payments or bookings.

Can I Make Calls from the Old SIM?

Keeping the old SIM active does not make international roaming calls free. Outgoing calls, answered incoming calls and voicemail retrieval can incur charges. A missed call may be safer than answering when the tariff is unknown, but voicemail forwarding rules can also create costs.

For internet calls, supported apps can use NoveSIM data. Conventional calls continue to use the line that owns the number. Check the selected voice line before tapping a number in the Phone app.

Why Automatic Data Switching Can Cause Charges

Some phones can move mobile data to the other SIM when the preferred line has weak coverage or during a call. That feature is convenient at home but risky when the fallback is an expensive roaming SIM.

Turn automatic switching off before travelling if cost control is the priority. If mobile data stops during a call on the old SIM, that may be the expected result of keeping switching disabled rather than a fault with the eSIM.

Does Data Roaming Need to Be On?

For a NoveSIM travel eSIM, Data Roaming normally needs to be enabled on the travel line because the plan connects through supported partner networks. This setting does not charge the old SIM when it is applied to the correct line.

Always check the label at the top of the settings screen before changing roaming. The full explanation is available in the NoveSIM Data Roaming guide.

What If the Travel eSIM Does Not Connect?

Confirm that the travel profile is present and switched on.
Verify that the NoveSIM line is selected for Mobile Data.
Check that Data Roaming is on for the travel line, not the old SIM.
Disable automatic data switching.
Wait several minutes and toggle Airplane Mode once.
Test more than one ordinary website or app.
If manual APN entry is required, use data.esim with username and password blank.

Do not delete the installed eSIM while troubleshooting unless NoveSIM Support specifically tells you to do so. Removing the old physical SIM is also unnecessary unless you are isolating a device problem and can reinsert it safely.

FAQ

Can I use an eSIM without removing my old SIM card?

Yes, if the exact phone supports Dual SIM and is unlocked. Keep the old SIM for its number and select the travel eSIM for mobile data.

Will adding an eSIM deactivate my physical SIM?

No. Adding an eSIM does not normally cancel the physical SIM. Each line remains controlled by its provider, although the device may limit which combinations can be active together.

Can I receive SMS on my old number while using eSIM data?

Often yes, when the old line remains enabled and can register abroad. Availability and charges depend on the home carrier, so verify its roaming terms before travel.

Which SIM should have Data Roaming turned on?

Enable Data Roaming on the NoveSIM travel eSIM. Keep it off on the old SIM if you want to avoid home-carrier mobile-data roaming.

Final Recommendation

Use the eSIM without removing the old SIM when your exact phone supports the required Dual SIM combination. Label both lines so that the number-owning SIM and travel-data eSIM cannot be confused.

Select NoveSIM for Mobile Data, enable roaming on that travel line and disable roaming and automatic data switching for the old SIM when controlling costs.

Keep the old number available only for the calls, SMS or verification messages you genuinely need, and check its carrier tariff because leaving a line enabled does not remove voice or messaging roaming charges.