How to Use Dual SIM with eSIM While Travelling

Why Dual SIM with eSIM Is the Best Travel Hack

Travelling with two active mobile lines—your usual number and a local or travel data plan—lets you stay connected without surprise bills. With eSIM, you can add a temporary data plan digitally and keep your physical SIM (or existing eSIM) for calls and texts to your regular number. The result: you use affordable local data while friends, family, and banks can still reach you on your home number.

In this guide, you’ll learn how Dual SIM works, how to set it up on iPhone and Android, how to manage calls and messaging apps, and how to avoid roaming surprises. We’ll also share practical tips from the road, plus common pitfalls to sidestep. Where it makes sense, we’ll show how an IQ Travel eSIM can slot right into your setup for smooth, low-cost data abroad.

What Dual SIM and eSIM Actually Mean

Dual SIM: Your phone supports two mobile lines at once. Most devices use Dual SIM Dual Standby (DSDS), meaning both lines are “on” for incoming communication, but only one handles active data/calls at a time.
eSIM (embedded SIM): A digital SIM built into your phone. You can install plans by scanning a QR code or using an app—no plastic card required. Many phones let you store multiple eSIM profiles and switch between them as needed.

Common dual setups for travellers:

Physical SIM (home) + eSIM (travel data)
eSIM (home) + eSIM (travel data) on eSIM-only phones (e.g., newer iPhones in some regions)
Physical SIM (local calls) + eSIM (regional data plan)

Why Use Dual SIM While Travelling

Cut roaming costs: Keep your home SIM active for calls/SMS, but use local/regional eSIM for data at local rates.
Stay reachable: Banks, two-factor codes, and urgent contacts can still hit your home number.
Better coverage: If your travel eSIM partners with multiple networks, you can switch to the strongest signal.
Convenience: Install and activate plans instantly—great for multi-country trips or last-minute changes.

IQ Travel makes this easy with pay-as-you-go country and regional eSIM data plans. You can install a plan before you fly and activate it when you land, so you’re online the moment the plane doors open.

Check Your Phone’s Compatibility First

Before you buy any eSIM plan:

Confirm eSIM support:

iPhone XR/XS and newer support at least one eSIM. Newer iPhones can use two eSIMs simultaneously.
Many Android flagships (Google Pixel 3+ [varies by region], Samsung Galaxy S20+ and newer, select OnePlus, Motorola, etc.) support eSIM. Check Settings or the manufacturer’s site.

Ensure the device is carrier-unlocked if you plan to use non-home carriers.
Check Dual SIM behavior:

Most phones are DSDS, which is fine. If you’re on a call on one line, the other may be temporarily unavailable.

Update your OS:

Install the latest iOS/Android update for better eSIM stability and 5G support.

Tip: Not all carriers support Wi‑Fi Calling or Visual Voicemail abroad. If those matter to you, ask your home carrier before you go.

Pre-Trip Checklist: Set Yourself Up for Success

Back up your phone.
Update iOS/Android to the latest version.
Verify eSIM compatibility and carrier unlock status.
Choose your travel data plan:
Country vs. regional coverage (e.g., Europe, Southeast Asia).
Duration that matches your trip.
Hotspot/tethering allowed (IQ Travel plans generally support hotspot; check plan details).
Review when the plan “starts”:
Many eSIMs activate on first connection in the destination.
Some plans start counting from installation—read the fine print.
Gather installation details:
You’ll usually receive a QR code and/or manual activation code (SM-DP+ address + activation code).
Prepare app logins:
Banking, rideshare, maps—enable 2FA methods that don’t require SMS if possible (authenticator app, backup codes).
Download offline essentials:
Maps, translation packs, airline and hotel apps, boarding passes.
Alert important contacts:
Let family or colleagues know you’ll keep your usual number for calls/SMS but use data on your travel line.

Installing an eSIM: General Steps

From your eSIM provider (for example, IQ Travel), purchase a plan for your destination.
Receive the eSIM details via email or app:
QR code or manual entry (SM-DP+ address and activation code).
Have a stable Wi‑Fi connection for installation.
Keep the QR code on another screen or printed—don’t try to scan from the same phone.

Note: APN (Access Point Name) usually configures automatically. If your provider specifies a manual APN, enter it exactly as given.

iPhone: Set Up Dual SIM with eSIM

On iPhone (XR/XS and newer), you can use one physical SIM + one eSIM, or dual eSIM on supported models.

Install the eSIM

Settings > Cellular (or Mobile Service) > Add eSIM.
Scan the QR code, or choose “Use QR Code”/“Enter Details Manually” and input the SM-DP+ and activation code.
Wait for the plan to install.

Label your lines

You’ll be prompted to label each line (e.g., “Home” and “Travel Data (IQ Travel)”).
Clear labels help avoid accidental roaming.

Choose defaults

Default Voice Line: Typically set to “Home” if you want calls/SMS on your usual number.
iMessage & FaceTime: Settings > Messages > Send & Receive, and Settings > FaceTime. Choose the number and email(s) you prefer. If you change which number iMessage uses, Apple may send a carrier SMS to activate—this could incur a roaming SMS fee.

Set data to the travel eSIM

Settings > Cellular > Cellular Data > select your travel eSIM.
Turn Data Roaming ON for the travel eSIM.
Turn Data Roaming OFF for your home line.
Important: Turn OFF “Allow Cellular Data Switching” to prevent the iPhone from using your home line for data during calls.

Network and 5G options

Settings > Cellular > [Travel eSIM] > Voice & Data: choose 5G Auto/On or LTE depending on coverage and battery needs.
If coverage is patchy, try manual network selection under Network Selection.

Test before you go (if your plan allows)

Ensure the eSIM profile installs correctly.
Avoid triggering activation early if your plan starts on first use in destination.

Android: Set Up Dual SIM with eSIM

Menus vary by brand, but the logic is similar on Samsung, Google Pixel, and others.

Install the eSIM

Settings > Connections (or Network & Internet) > SIM Manager (or SIMs) > Add eSIM.
Scan QR or enter activation details manually.
Follow the on-screen prompts to complete.

Name your SIMs

SIM Manager > rename lines to “Home” and “Travel Data (IQ Travel).”

Set defaults

Preferred SIM for Calls: usually “Home” if you want to keep your number for voice.
Preferred SIM for SMS: usually “Home” (bank codes, 2FA).
Mobile Data: set to your travel eSIM.

Roaming and network settings

Ensure Data Roaming is ON for the travel eSIM and OFF for the home SIM.
Network Mode: choose 5G/LTE/Auto for the travel eSIM as available.
If needed, manually select a partner network in Mobile Networks > Network operators.

Hotspot

Confirm that hotspot/tethering works with your travel eSIM plan. Most IQ Travel plans allow this—helpful for laptops and tablets.

Managing Calls, Messages, and Your Apps

Regular calls and SMS
You can keep your home SIM as the default for calls and texts. You’ll receive calls/SMS on that number as long as the line is on and has roaming for voice/SMS (data roaming can stay off).
Inbound SMS while roaming may be free or charged depending on your carrier—check their policy.

WhatsApp, Signal, Telegram
These work over data from your travel eSIM. Your WhatsApp account stays tied to the number you registered with, not the data line.
If WhatsApp asks to verify a new number after SIM changes, choose “Not now” unless you really want to change your account number.

iMessage and FaceTime
iMessage/FaceTime can run over your travel data. If you re-enable iMessage with a different number, the phone may send an international SMS for activation—this can incur a fee. Avoid toggling repeatedly while abroad.

Wi‑Fi Calling
Handy if your home carrier supports it overseas; calls and SMS can route over Wi‑Fi or your travel data.
Some carriers block Wi‑Fi Calling abroad—ask before departure.

Voicemail
Visual Voicemail may not work when roaming. You may need to dial your voicemail number.
Consider a short greeting explaining you’re travelling and best reached via messaging apps.

Call forwarding
If you forward your home number to another number or a VoIP service, set it up before leaving. Domestic forwarding often bills as a local call; consult your carrier.

Avoiding Surprise Charges

Turn off data roaming on your home SIM
iPhone: Settings > Cellular > [Home SIM] > Data Roaming OFF.
Android: Settings > Connections/Network > Mobile networks > [Home SIM] > Data Roaming OFF.

Lock data to your travel eSIM
iPhone: Set Cellular Data to the travel eSIM and disable “Allow Cellular Data Switching.”
Android: Set Mobile Data to the travel eSIM and disable any “Auto data switching” features.

Watch SMS fees
Banks and services that send 2FA codes by SMS may trigger roaming SMS charges. Use app-based 2FA where possible.

Control background sync
Temporarily disable large cloud syncs (iCloud Photos, Google Photos) and auto app updates.
Lower streaming quality; download content over Wi‑Fi.

Monitor usage
iPhone: Settings > Cellular > [Travel eSIM] > track data.
Android: Settings > Network & Internet > Data usage.
Many providers, including IQ Travel, also show usage in your account or app.

Smarter Data Management on the Road

Pre-download maps and translation packs.
Cache playlists and shows on Wi‑Fi.
Use offline modes in Google Maps and Spotify/YouTube Music.
Enable Data Saver/Low Data Mode:
iPhone: Settings > Cellular > Data Mode > Low Data Mode.
Android: Settings > Network & Internet > Data Saver.

Battery and Performance Tips with Dual SIM

Running two active lines uses more power. To extend battery life:

Disable the line you don’t need temporarily:
iPhone: Settings > Cellular > toggle off a line.
Android: SIM Manager > toggle off a SIM.
Prefer LTE if 5G coverage is weak—searching for 5G drains power.
Use Low Power Mode (iPhone) or Battery Saver (Android).
Turn off Personal Hotspot when not in use.
Avoid constant network scanning; pick a stable network manually if auto-switching is flaky.

Troubleshooting: Common Dual SIM + eSIM Issues

No data on travel eSIM
Ensure Mobile Data is set to the travel eSIM.
Turn Data Roaming ON for the travel eSIM.
Toggle Airplane Mode for 10 seconds, or restart the phone.
Try manual network selection; pick a listed partner network.
Check APN settings if your provider specifies a manual APN.

Calls/SMS using the wrong line
Double-check Default Voice Line and Default SMS line.
On iPhone, disable “Allow Cellular Data Switching.”
In the dialer or Messages, many phones let you choose the line per contact/thread.

iMessage not activating
Confirm the correct number is selected in Send & Receive.
Your home line may need the ability to send/receive one activation SMS. This can incur a small roaming charge.

WhatsApp prompts to change number
Select “Not now” to keep your original account number. Ensure mobile data is active on the travel eSIM.

eSIM won’t install
Ensure you’re on Wi‑Fi during installation.
Verify you haven’t exceeded the device’s limit for installed eSIM profiles.
Recheck the SM-DP+ address and activation code (watch for typos).
Contact your provider’s support—IQ Travel support can resend the QR or help with manual installation.

Flaky coverage or slow speeds
Move to a less congested band by reselecting the network, or toggle 5G/LTE.
Try another partner network if available.
Use a regional plan if you’re near borders to avoid network handoffs.

Multi-Country Trips: Make Dual SIM Work Harder

Use a regional eSIM from IQ Travel to cover multiple countries under one plan.
Keep your home line active for calls/SMS; let the regional eSIM handle all data hopping across borders.
If you need multiple eSIMs for different legs, pre-install them and enable the correct one for each country—rename them by country (“EU Data,” “Japan Data”) for clarity.

Privacy and Security Considerations

SIM registration rules: Some countries require ID verification for mobile service. eSIM providers, including IQ Travel, may need a quick KYC check depending on local laws.
Public Wi‑Fi: Use your travel eSIM for sensitive tasks instead of open Wi‑Fi, or use a reputable VPN.
2FA hygiene: Prefer authenticator apps over SMS where possible.

Where IQ Travel Fits In

Fast setup: Buy online, receive your QR instantly, install over Wi‑Fi—no stores, no waiting.
Flexible coverage: Country-specific and regional plans—ideal for multi-stop itineraries.
Hotspot-friendly: Most plans allow tethering so your laptop and tablet can piggyback.
Easy budgeting: Transparent data allowances and durations; top up when needed.
Keep your number: Use IQ Travel for data while your home SIM remains reachable for calls and SMS.

You can install an IQ Travel eSIM before departure and activate it upon arrival—perfect for landing-day logistics like ride-hailing, translations, and directions without hunting for a SIM shop.

Quick Reference: Dual SIM Travel Setup

Buy a travel eSIM (e.g., IQ Travel) for your destination.
Install over Wi‑Fi via QR or manual code.
Label lines clearly: “Home” and “Travel Data (IQ Travel).”
Set Default Voice/SMS to Home; set Mobile Data to Travel eSIM.
Turn Data Roaming ON for Travel; OFF for Home.
Disable data switching to prevent accidental home data.
Confirm hotspot works and download offline content.
Monitor usage and adjust network mode for coverage/battery.
Keep WhatsApp/iMessage tied to your preferred number.
Toggle off a line if you need to save battery or avoid interruptions.

FAQs

Will my phone ring on both numbers?
Yes, with DSDS both lines are on standby. If you’re on a voice call on one line, the other may be temporarily unreachable.

Can I use 5G on the travel eSIM?
Usually yes, subject to device, network, and plan. Make sure 5G is enabled for that line and the network supports it.

Does installing an eSIM start the plan immediately?
It depends on the provider. Many plans (including IQ Travel’s) start when you first connect in the destination, not when you install—check your plan details.

Can I have multiple eSIMs?
Most modern phones let you store several eSIM profiles and activate one (or two on newer iPhones) at a time.

Will WhatsApp change my number automatically?
No. WhatsApp will keep your existing account unless you explicitly change the number in its settings.

Conclusion

Dual SIM with eSIM is the simplest way to stay reachable and control costs while travelling. Keep your home number for calls and texts, add a travel eSIM for affordable data, and fine-tune your settings to avoid roaming surprises. With a few minutes of prep—label lines, lock data to your travel eSIM, and confirm roaming settings—you’ll land connected and confident.

If you want a hassle-free setup with broad coverage and easy top-ups, IQ Travel’s eSIM plans slot neatly into this Dual SIM workflow. Install before you fly, turn it on when you land, and enjoy local-speed data while your regular number stays right where people expect it.