One of the most common questions we regularly hear from Australian travellers heading overseas is surprisingly simple:
“Can I keep my normal Australian number while using a travel eSIM overseas?”
The short answer, although a little vague is yes — in most cases, you can.
Using your usual number is also something we do ourselves when travelling. On a recent trip to Spain and Ibiza, for example, we wanted our normal Australian numbers to stay active for things like banking verification codes, booking messages and important texts, while using a travel eSIM for everyday mobile data.
That meant we could still receive what we needed on our Australian numbers, while using mobile data for everything else such as Google Maps, WhatsApp, restaurant bookings, Uber, and everything else you tend to rely on when overseas.
And, importantly, we weren’t relying on expensive mobile data roaming while enjoying our time in Spain.
This is one of the biggest advantages of using a travel eSIM. You can keep your normal Telstra, Optus, Vodafone or other Australian SIM active for calls and texts, while using a separate travel eSIM for your all your mobile data.
In a nutshell, here’s how it works.
How does using two SIMs at once work?
Most modern smartphones such as iPhone, Samsung Galaxy, and Google Pixel support dual SIM functionality.
That means your phone can have:
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your normal Australian SIM or eSIM
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a separate travel eSIM
active at the same time.
Your Australian number can remain connected for calls and SMS, while your travel eSIM handles your mobile data.
Think of it as giving each SIM a different job.
Your Australian SIM keeps your usual phone number.
Your FlexySim travel eSIM provides the data you use for all browsing, Google Maps, WhatsApp, email, social media, Uber, and everything else you normally do online while travelling.
Can I still receive SMS messages on my Australian number?
Usually, yes.
This is one of the main reasons travellers choose to keep their Australian SIM switched on.
It can be particularly useful for receiving important information such as :
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bank verification codes
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two-factor authentication messages
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airline notifications
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booking confirmations
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important family messages
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security alerts
Just remember that while receiving an SMS overseas is often free, sending SMS messages or making and receiving calls may incur international roaming charges depending on your Australian mobile provider and plan.
It is really important to check your usual providers international roaming rates, and policy for the countries you are visiting before you travel.
The important part: turn data roaming off on your Australian SIM
This is probably the most important step.
If your goal is to avoid expensive international roaming charges, make sure data roaming is switched off for your Australian SIM.
Then select your travel eSIM as the SIM used for mobile data.
That way, your phone should use the travel eSIM whenever it needs internet access.
Your Australian SIM can stay active for calls and texts without becoming your main data connection.
This is generally how we set our own phones up when travelling with FlexySim.
What about WhatsApp?
The good news is that WhatsApp normally keeps working with your existing Australian number.
You do not need to change your WhatsApp number just because you are using a travel eSIM.
Once your travel eSIM is providing mobile data, WhatsApp should continue working just as it does at home.
Your contacts still see your normal number, your chats remain the same and you can continue sending messages and making WhatsApp calls using your travel data.
For us, this is one of the simplest parts of travelling with an eSIM — once the data connection is active, apps like WhatsApp, Messenger, iMessage and Google Maps generally just continue working normally.
Can I make normal phone calls using my Australian number?
Yes, but this is where you need to be a little careful.
If you make a traditional mobile call using your Australian SIM while overseas, your Australian carrier may charge international roaming fees.
The same can apply when receiving calls.
Because of this, many travellers use internet-based calling apps instead, such as:
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WhatsApp
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FaceTime Audio
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Messenger
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Signal
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Teams
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Zoom
These calls use your travel eSIM data rather than the roaming call network.
If you do need to make or receive normal calls on your Australian number, check your usual providers roaming charges first.
What happens if I accidentally leave mobile data on for my Australian SIM?
This is where roaming charges can creep in.
Phones constantly use small amounts of background data.
Weather updates, email syncing, app notifications, cloud backups and social media apps can all quietly use data even when you are not actively using your phone.
That is why we always recommend checking your settings carefully before or shortly after you land.
Your travel eSIM should be selected as your primary mobile data SIM, and data roaming should be disabled on your Australian SIM.
A few minutes checking these settings can potentially save you a nasty bill surprise when you return home.
How to set it up on an iPhone
The exact wording may vary slightly depending on your iOS version and region, but generally:
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Open Settings.
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Go to Mobile or Cellular.
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Make sure both your Australian SIM and travel eSIM are switched on.
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Tap Mobile Data.
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Select your FlexySim eSIM as the mobile data line.
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Open your Australian SIM settings.
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Make sure Data Roaming is switched off.
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Open your FlexySim eSIM settings.
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Make sure Data Roaming is switched on if required for the eSIM to connect.
That final point can sometimes seem confusing.
With many travel eSIMs, data roaming actually needs to be switched on for the travel eSIM itself, because the eSIM connects through partner networks overseas.
The important distinction is:
Australian SIM: data roaming OFF
Travel eSIM: data roaming ON, where required
How to set it up on Android
Android settings vary a little more between manufacturers such as Samsung, Google Pixel and others, but the principle is the same.
Look for settings such as:
Settings → Connections → SIM Manager
or:
Settings → Network & Internet → SIMs
Then:
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Make sure your Australian SIM remains switched on.
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Make sure your travel eSIM is switched on.
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Select the travel eSIM for mobile data.
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Turn data roaming off for your Australian SIM.
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Enable data roaming on the travel eSIM if required.
If your travel eSIM does not connect immediately, restarting your phone or briefly switching Airplane Mode on and off can often help it register with the local network.
Do I need to remove my Australian SIM?
Usually, no.
In fact, we generally prefer keeping it installed.
Removing your normal SIM can make it harder to receive important SMS messages and verification codes while travelling.
The whole advantage of a dual-SIM phone is that you can keep your normal Australian number available while using a separate eSIM for data.
There are some situations where a traveller may choose to switch their Australian SIM off entirely, particularly if they are worried about accidental roaming charges, but removing it physically is generally unnecessary.
Can my Australian number still receive banking codes?
Usually, yes, as long as your Australian SIM remains active and can connect to a roaming network overseas.
This is particularly useful when logging into banking apps, making online purchases or accessing accounts that require two-factor authentication.
That said, every Australian provider handles international roaming slightly differently, so it is worth checking your provider’s policies before you leave.
Will iMessage still work with my Australian number?
In most cases, yes.
On an iPhone, iMessage can continue working with your existing Australian number while your travel eSIM supplies the internet connection.
We recommend checking:
Settings → Apps → Messages → Send & Receive
and confirming that your normal phone number and Apple ID are still selected correctly.
Avoid unnecessarily changing your iMessage number when installing your travel eSIM.
A real-world example
A typical setup for someone travelling from Melbourne to Europe might look like this:
Your normal Australian SIM stays active so you can still receive important SMS messages.
You install a FlexySim Europe eSIM before leaving Australia.
When you arrive in Europe, you switch your mobile data connection to FlexySim.
Your Australian SIM remains connected for calls and SMS, but mobile data roaming on that SIM stays switched off.
You then use your travel eSIM for Google Maps, restaurant bookings, train apps, Uber, WhatsApp, Instagram and general browsing.
For most travellers, that is all there is to it.
A few mistakes we see travellers make
Over the years, there are a few common issues that come up again and again.
Leaving the Australian SIM selected for mobile data
This can lead to roaming charges.
Always check which SIM is selected for mobile data.
Turning roaming off on the travel eSIM
Travel eSIMs need data roaming switched on in order to connect to local partner networks.
If your eSIM is installed but not working, this is one of the first settings worth checking.
Switching the Australian SIM off unnecessarily
You can usually leave it active if you still want to receive SMS messages.
Changing your WhatsApp number
You generally do not need to change anything inside WhatsApp just because you have installed a travel eSIM.
Installing the eSIM without a stable internet connection
You normally need a stable Wi-Fi or mobile connection to install an eSIM.
We usually suggest installing your FlexySim before you leave Australia, while you still have reliable internet access.
You can then activate and use it when you arrive at your destination.
So, can you keep your Australian number while travelling?
Absolutely.
For most modern smartphones, using an international travel eSIM does not mean giving up your normal phone number.
You can keep your Australian SIM active for texts and important calls while using your travel eSIM for affordable mobile data.
For us, that is one of the biggest reasons eSIMs make travelling easier.
No swapping tiny plastic SIM cards in an airport.
No losing access to your usual number.
And, if you configure your phone correctly, no relying on expensive mobile data roaming from your Australian provider.
Travelling soon?
Safe Travels from the FlexySim team
