How to Keep Your Home Number While Using a Japan eSIM

Short answer: install ANZROAM’s Japan eSIM as your data line, and leave your home SIM or eSIM active on the other slot for calls, texts, and verification codes to your existing Australian or New Zealand number. This only works on an unlocked, eSIM-capable device that can keep a second line active at once, and what “capable” means depends on your exact phone (see the FAQ below). Even with the Japan eSIM handling data alone, keeping your home line switched on overseas can still trigger roaming charges, and which actions trigger those charges differs by carrier and plan. Check your home carrier’s roaming policy before you fly, not after you land.

Which line does what

Line	What it’s for	What it isn’t for
Japan eSIM (travel line)	Mobile data: maps, messaging apps, browsing, app-based calls (WhatsApp, LINE, FaceTime)	Ordinary calls, SMS, or receiving texts to your home number
Home SIM or eSIM (existing number)	Ordinary calls, SMS, and OTP/2FA codes to your existing number, if your device and carrier support it	Mobile data in Japan, unless you want to pay home roaming data rates

Before you fly: check these first

Confirm your phone is unlocked and supports eSIM. Whether it can keep a second line active at once is model-specific; see the device FAQ below.
Install the eSIM profile before you travel; ANZROAM’s FAQ recommends a stable Wi-Fi connection for this.
Ask your home carrier exactly which actions trigger roaming charges on your plan: this varies by carrier.
Keep your ANZROAM order and installation email private, for setup and as a support reference. Don’t rely on a saved QR screenshot to reinstall later, and don’t delete an installed profile unless support says to.

Setting up dual SIM on iPhone

Your model and where you bought it both matter here, so check Apple’s Dual SIM page for your specific model before assuming either capability below applies. In general, iPhone XS, XS Max, XR and newer can run a physical SIM alongside one eSIM; two eSIMs at once, which is what most people need here, requires an iPhone 13 or newer. Region matters too: mainland China currently limits eSIM support to iPhone Air and iPhone 17e, and some Hong Kong/Macao models use dual nano-SIM instead of eSIM. Installing a travel eSIM offers using it alone or alongside your current line; the second option keeps your home line active alongside the travel eSIM, if your iPhone supports both at once.

The data-line selector and each line’s Data Roaming toggle live under Settings, though Apple’s labelling isn’t consistent: current guidance points to Mobile Service (or Cellular) > Mobile Data (or Cellular Data). Check Apple’s travel eSIM guide against your own screen, since wording depends on model and iOS version.

Setting up dual SIM on Android (Pixel)

Pixel has its own specific boundaries. Pixel 3a and later generally support one physical SIM plus one eSIM, but Google’s Pixel Dual SIM guide lists real exceptions: a Pixel 3a bought in Japan can’t run two SIMs at all, Pixel 7/7 Pro or newer can run two eSIMs when the carrier allows it, and Pixel 10 and newer bought in the US (except Pixel 10 Pro Fold) are eSIM-only. Support depends on carrier as well as phone, so check your exact model and where you bought it. Per-SIM Data Roaming lives in Settings > Network & internet > SIMs (Google’s mobile network settings page; some steps only apply to Android 11+). Menu names differ on Samsung or other brands.

Automatic data switching, covered next, involves a genuine tradeoff: turning it off stops your home line quietly picking up roaming data, but on Pixel 8a and newer, receiving a call on your second line during a call on the first needs both SIMs’ data on, automatic switching on, and carrier-supported Wi-Fi calling. Check exact requirements before switching it off if simultaneous calls matter to you.

Setting the Japan eSIM as your data line

Four settings finish the job, once both lines are installed:

Data line: set the Japan eSIM as your active data line, using the selector covered above.
Travel eSIM roaming: turn data roaming ON for the Japan eSIM, since it connects to Japanese networks, per ANZROAM’s FAQ.
Home line roaming: turn data roaming OFF for your home line, and turn off automatic data switching if offered (Pixel tradeoff above).
Default calls and messages: set your home line as default for calls and SMS, or “ask every time” if offered. Skipping this means an outbound call or text might not use the line you expect.

What “keeping your number” actually means

Keeping your home number active doesn’t move it onto the Japan eSIM. The Japan product is data-only: no number, SMS, or traditional calls. If a call or text to your home number is successfully delivered, it’s handled by your home carrier’s service, the same as before you installed a travel eSIM. Which line an outbound call or text uses is separate, depending on the default line you set in step 4 above, or on choosing manually each time.

ANZROAM can’t guarantee you’ll receive a text or OTP on your home number in Japan; that depends on your carrier’s roaming agreements, whether your phone has connected to a local network, who’s sending it, and your account conditions. A test call or text can itself trigger roaming charges (more below), so weigh that first, and a successful test doesn’t guarantee every later OTP behaves the same way.

Turning off roaming on your home line isn’t a guarantee

Switching data roaming off for your home SIM stops that line using mobile data while you’re away. It doesn’t confirm calls, SMS, voicemail, or any roaming pass are free. Home-carrier rules differ, and enabling roaming, starting a daily roaming service or pass, and actually being charged are separate questions, though the same event, like your phone connecting to a network, can satisfy more than one at once. Telstra and Optus currently describe usage-based triggers: calls, sent SMS, or data use. 2degrees’ current page is less clean-cut: it lists the same usage triggers but elsewhere also implies simply connecting to a local network can itself be charged for the day. Treat connecting your home line as potentially chargeable unless your own carrier confirms otherwise, and check directly rather than assuming any of this generalises; ANZROAM doesn’t set, control, or predict home-carrier billing.

Arrival checklist

Confirm the Japan eSIM shows as your active data line and that you have a connection.
Check data roaming is on for the Japan eSIM and off for your home line.
To confirm your home number is reachable, check roaming charges first: a test call or text can itself trigger charges, so treat this as optional, not routine.
For app calls, confirm they use the Japan eSIM’s data, not your home line’s.

Return-home reset checklist

Switch your data line back to your home SIM.
Turn data roaming back off for the Japan eSIM (good hygiene, even without local coverage at home).
Re-enable automatic data switching if you turned it off.
Leave the profile installed if you plan to return; if you need to reinstall later, contact ANZROAM support rather than assuming a saved QR code will still work.

Frequently asked questions

Does the Japan eSIM come with my own phone number?
No. It’s data-only. Your existing AU or NZ number stays on your home SIM or eSIM, running as a separate line if your device supports it.

Will I definitely be able to receive texts and calls on my home number in Japan?
Not guaranteed; it depends on your phone connecting to a local network, your carrier’s roaming agreements, and account settings. A test call or text can itself trigger charges, so weigh that first.

Do I need to turn on data roaming for the Japan eSIM?
Usually yes. ANZROAM’s FAQ explains data roaming typically needs to be on for the ANZROAM line itself, since it connects to Japanese networks.

Does turning off roaming on my home line mean I won’t be charged anything?
No. It stops mobile data use, but roaming rules differ by carrier: enabling roaming, starting a daily pass, and being charged are separate questions that can overlap. Some carriers only charge for actual calls, texts, or data; others’ own pages suggest simply connecting to a network can be charged too. Check your carrier’s specific policy before you fly.

What if my phone doesn’t support eSIM, or supports eSIM but not two lines at once?
No eSIM support means you can’t use this Japan eSIM. eSIM without two simultaneous lines means you can use it alone for data, but not keep your home line active too on that device. Compatible dual-SIM means you can run both lines together, as this guide describes.

Get started

Check the Japan eSIM product page for current plans, and see the Japan eSIM Guide for the wider picture. More setup guides are on the eSIM & Connectivity hub.