Short answer: On Boost Mobile (Australia), your number is at risk after 6 months with no recharge. Otherwise the number expires and is reallocated to another customer.
How long you have on Boost Mobile (Australia)
That Boost Mobile (Australia) SIM you forgot about can stop being yours sooner than you'd think. On Boost Mobile (Australia), the number is at risk after 6 months with no recharge. Boost runs on the full Telstra network and shares Telstra's prepaid terms, including the 6-month recharge-only period.
A working SIM that still shows signal doesn't mean the number is still yours — on prepaid, the number is tied to activity, not to whether the card powers on. (See what happens when you stop using a prepaid SIM for the full lifecycle.)
Can you get your Boost Mobile (Australia) number back?
Recharge within the 6-month recharge-only period to keep the number. Otherwise the number expires and is reallocated to another customer. Once a number has been released to the pool and reassigned to someone else, it's gone for good.
What counts as keeping it active
For almost every carrier the rule is the same: it has to be something they bill — an outgoing call or SMS, paid mobile data, or a top-up or paid add-on. Internet apps like WhatsApp, iMessage and FaceTime run over data and usually don't count, and incoming calls and voicemail often don't either. The cheapest way to stay active is one small billable action before the deadline — more in how to keep a prepaid SIM active without spending money.
Comparing carriers? See the full prepaid expiration policies table for the US, UK, Australia and Canada.
Don't lose your Boost Mobile (Australia) number by accident
KeepSim gives this line its own countdown, warns you on your Home Screen before the deadline, and lets you fire a keep-alive action in one tap. Local-first, no account.
Get KeepSim on the App StoreCommon questions
How long before Boost Mobile (Australia) recycles your number?
On Boost Mobile (Australia), your number is at risk after 6 months with no recharge. Otherwise the number expires and is reallocated to another customer.
Can you get your Boost Mobile (Australia) number back?
Recharge within the 6-month recharge-only period to keep the number. Once the number has been released and reassigned, getting it back is almost never possible.
Does using WhatsApp keep the number active?
Usually no. WhatsApp, iMessage and similar apps run over data or Wi-Fi and don't count as carrier activity. You typically need a billable call, text, paid data, or a top-up.
Last verified June 2026 against Boost Mobile AU help. Carrier policies change often and depend on your exact plan and country — treat this as a starting point, not legal advice, and confirm the current rule with Boost Mobile (Australia) before relying on it. KeepSim is a personal reminder tool; it does not provide telecom service or keep numbers active on your behalf.