Moving au service from a physical SIM to an eSIM
Converting an au mobile line from a physical SIM to an eSIM means replacing the removable card with a downloadable subscriber profile while keeping the same au phone number and plan. It is not simply a new handset purchase. au must issue the profile, and the phone must be compatible, carrier-unlocked and linked to an active account. Careful preparation prevents the old card from being disabled before the replacement is ready.
Australian travellers should first establish where the au line will be used. au operates in Japan, while everyday mobile service in Australia is dominated by Telstra, Optus and Vodafone. Visitors can keep an Australian number active for two-factor authentication while using au in Japan, but au is not a local Australian network. For residents, a Japanese au eSIM may offer little coverage in Australia, so the change should be planned around travel to Japan or an existing Japanese line.
Check au eligibility and handset compatibility
Start with the au account and line. The physical SIM should be active under your name or business account, and you need the au mobile number, the SIM’s ICCID and the account PIN used in My au or au Web. Some prepaid, corporate and special-device contracts cannot be converted online, so au may need to verify eligibility. If the line is inactive, ask au to reactivate it with an eSIM rather than ordering a profile first.
Next, verify the exact handset model, not merely that its specification page says eSIM. Australian-market phones commonly support LTE bands 1, 3, 5, 7 and 28 and 5G band n78. au also uses LTE bands 11 and 18, while its 5G footprint includes n79 in some locations. Many recent multi-band phones cover these bands, but some older or operator-locked models do not. An au phone sold in Japan may also be SIM-locked. Confirm the model number, IMEI and lock status before changing the line.
Do not mix up two separate migrations. Moving an au physical SIM to an au eSIM can preserve the existing Japanese number. Transferring an Australian +61 number to au is an overseas number-porting request and is not automatically available; Australian domestic transfers follow ACMA rules and local carrier procedures, not au’s Japanese process. If retaining +61 for banking, workplace systems and messages is the priority, keep the Australian SIM active and treat the au eSIM as a separate Japanese line.
Prepare the phone and secure your account
Back up the handset before au issues a profile. Update iOS or Android and the au service app, install essential authentication apps, charge the phone and save the account credentials needed if the device is replaced. Record the physical SIM’s ICCID, but keep the card installed until the eSIM is active. Do not factory-reset the handset at this stage.
Treat the activation QR code and activation code like a password. They should not appear in photos sent to forums, technicians or chat groups, and activation should use a private connection. Australian organisations should also check how au support records are handled if employee phones or customer data are involved; the Privacy Act 1988 and its Privacy Principles can govern the Australian organisation’s handling of personal information even when the provider is overseas.
Carry a backup payment method and review payment options before departure. Otherwise, activation trouble can also interrupt tap-to-pay for a Brisbane coffee, Sydney groceries or daily travel with Melbourne’s Myki and Adelaide’s go card. If the Australian SIM will provide data in Japan, check roaming charges before switching it off. For a long stay, a local prepaid SIM or travel eSIM may be cheaper, while the Australian line remains useful for calls and one-time codes.
Compare removable and embedded SIM options
The practical differences are:
| Feature | Physical SIM | eSIM |
|---|---|---|
| Format | Removable plastic card | Digital subscriber profile stored securely in the handset |
| Setup | Insert the card into the slot | Scan a QR code or enter an activation code |
| au number | The card carries the line when assigned to the account | au can attach the same number to the replacement profile |
| Hardware | Requires a physical SIM slot | Requires eSIM-capable hardware; active-profile limits vary by model |
| Changing phones | Usually straightforward once the line is unlocked and compatible | au must issue or transfer a fresh profile to the new device |
| Loss or damage | The card can be replaced, although the number may be exposed to misuse | Account controls and remote deletion can protect a lost handset’s profile |
A physical SIM remains useful when you regularly exchange phones, need a handset without eSIM support or want a visual check that a card is present. It is also the safer route if au has not confirmed eSIM eligibility for your contract. An eSIM is more convenient for a device used on the move and removes the risk of bending or leaving a card behind, but it cannot be transferred to another phone simply by inserting it elsewhere.
Some phones support a physical SIM and an eSIM simultaneously, while recent iPhones can use two active eSIMs. Other Android models allow only one active profile or reserve eSIM storage for a particular carrier. Check the manual rather than relying on a generic eSIM icon. au’s activation instructions must also match the model and plan. In Australia, a dual-SIM arrangement can keep +61 calls separate from a Japanese line, which is useful for people who need both networks during a long stay.
Activate the au eSIM profile
Request the replacement through My au, au Web, an authorised au shop or au support, depending on the account type. Choose the option to change or replace the SIM with an eSIM for the correct line, then check that the displayed number, plan and billing details match. au will issue a QR code or activation code, either in the app or as a document. Confirm whether the old physical SIM remains active until the profile finishes downloading.
On an iPhone, open Cellular or Mobile Data settings, choose Add eSIM and scan the code with the phone’s camera, following the on-screen label prompt. On Android, look for Add eSIM, Download SIM or eSIM manager under Connections, Network and internet or SIM settings; names vary by manufacturer and software version. You can normally download over Wi-Fi, although au may require a brief mobile-data connection to complete identity checks. Keep the code page open until the profile appears.
Give the line a clear label such as au Japan, wait for activation and make a short test call before relying on it. Send a message and open a web page outside Wi-Fi if the plan includes data. The new profile should carry the existing au number; a second temporary number is not normally created unless you deliberately request an additional line. Do not remove the old SIM until au confirms the replacement and all basic services work.
Common failures have identifiable causes. A blurred QR image can prevent scanning, while an eSIM unavailable message usually points to unsupported hardware, an active carrier lock or an incomplete software update. If activation is pending, restart once, use airplane mode for a minute and recheck network selection. Avoid repeatedly deleting and reinstalling the profile because that can complicate recovery. Give au support the IMEI, ICCID and exact error text, but never send the activation code through an unsecured message.
Test the service and plan Australian use
After activation, test calls, SMS, mobile data, Wi-Fi calling and voicemail where applicable. Confirm that 5G or LTE is selected, that the correct line handles calls and that the old physical SIM is disabled if it was replaced. A lost physical SIM should also be reported to au so its serial number can be blocked. Restarting the phone and checking for a carrier settings update often resolves an otherwise blank mobile-data icon.
Think carefully about ongoing Australian use. au is a Japanese network, so its coverage map does not describe coverage in Australia. Roaming availability, speed limits and data charges depend on the agreement attached to your line. A Telstra, Optus or Vodafone prepaid eSIM is generally more suitable for local Australian data, while au makes sense during travel to Japan or for a Japanese number. Keeping an active Australian SIM also protects access to banking and workplace authentication that may send messages to +61.
Face-to-face help can be valuable when activation screens are ambiguous. NSC operates authorised mobile phone shops across Fukushima and Miyagi, with au among the carriers it serves. If you are in Fukushima or Miyagi, check the store access details before travelling. Bring the handset, charging cable, au number, old SIM and proof of account access so the technician can check IMEI compatibility before changing the line.
Make the switch only when au has confirmed that the line can be converted and the handset can connect to au’s bands. Back up the phone, keep the physical SIM active until the eSIM is verified and protect the activation code as carefully as a password. This sequence preserves the number and provides a clear recovery route if activation stalls.
Book an au eSIM activation session with NSC before your next trip or arrange remote support through au, then complete the call, SMS and mobile-data checks before putting the old SIM away.