A spare number can still be worth keeping even when you barely make a call. It may be the number on an old bank account, a business card or a family contact list. The important question is whether you only want to retain it, or need it working every day for calls and verification texts.
Choose a service whose recharge validity suits how you use the number, and recharge before access expires if you need it to keep working. A provider’s disconnection grace period is not a promise that incoming texts remain available. When switching providers, arrange the transfer before cancelling the old service.
Recharge Expiry and Losing the Number Are Different Events
Telstra’s prepaid terms illustrate the distinction. After the network access period ends, its terms provide a six-month recharge-only period. During that period, ordinary service features are unavailable; the exceptions are emergency calling and access needed to recharge. If you do not recharge within that period, the service is disconnected and the number can be reallocated.
That does not make six months without recharging a useful strategy for a number receiving bank codes. It describes time to rescue the service, not six months of normal SMS access. Other providers have their own rules, so do not apply Telstra’s period to every prepaid SIM.
Source: Telstra: Pre-Paid Mobile Service Terms (PDF).
A Current Low-Use Example: amaysim As You Go
On 11 September 2026, amaysim advertises a $15 As You Go option with 365-day credit expiry. Standard calls to Australian mobiles and landlines cost 12 cents a minute and standard SMS cost 12 cents each. It includes no data allowance; usage is charged at 5 cents per MB, shown by amaysim as $51.20 per GB. Calls to 13 numbers are a separate 29 cents a minute, so the standard call rate does not cover every number.
This is a pay-as-you-go example, not a cheapest-plan ranking or a guarantee that $15 covers your year. Calls, texts and especially background mobile data can consume credit. If you use it as a secondary line, keep mobile data assigned to your main service and check that choice after changing phones.
Before paying, read the current offer and check renewal settings. For someone who actually uses the spare phone, included calls and data may matter more than the lowest starting recharge.
Source: amaysim: As You Go.
Do Not Confuse Turning Off Renewal With Cancelling
amaysim says customers who turn off plan auto-renew move to As You Go when the plan expires. That is different from asking it to cancel the service entirely. Its cancellation guidance warns that cancellation without a transfer loses the number, remaining credit and voicemail.
Keep a copy of the action you took and the next expiry date. If a screen says cancel service when you only mean stop the next plan renewal, stop and clarify the choice with support.
Source: amaysim: Suspend or cancel your plan.
Switch Providers Without Giving Up the Number
Check the old service is active and you can receive its texts. If the phone or SIM is lost or damaged, ask the receiving provider about alternative identity checks; Telstra documents in-store verification for a lost phone or SIM.
Start the new provider’s keep-my-number process. Have the account details ready. Telstra, for example, asks for the billed-service account number or matching prepaid date of birth, plus identity and contact details.
Complete the provider’s verification. Telstra documents an SMS verification step and requires the number to be active with the old provider.
Let the transfer complete rather than cancelling the old mobile service yourself. Telstra says the old service disconnects automatically after the transfer. Check any remaining device repayments or exit charges separately.
Source: Telstra: Transfer your mobile number.
Set Up a Reminder You Can Act On
Give the reminder a useful name, such as ‘Recharge spare amaysim number ending 1234’, and record the expiry date. Add a calendar reminder before expiry with enough time to fix a failed payment. A reminder that only says ‘SIM’ is hard to act on when you have more than one.
Once the service is active, ask someone to call and text it. If it receives account recovery messages, check that those accounts also have an up-to-date recovery method. Do this while you still control the number, not after you discover it has been disconnected.
This guide covers keeping an Australian service in use in Australia. Receiving texts overseas is a separate roaming question; confirm your particular plan’s support before relying on it while travelling.
Before You Leave the Spare SIM Alone
Sources and How This Was Checked
Checked against the official pages below on 11 September 2026. We have not performed these steps on a device or tested a customer account. The suggested test order and final checklist are editorial advice; provider and device requirements come from the linked documentation.
David Everson is Tech X Telco's mobile and broadband writer. He compares Australian mobile plans, NBN providers and prepaid deals, and tests the recharge processes, apps and tools readers ask about most. His focus is simple: helping Australians pay less for their phone and internet without losing the coverage they need.
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