Short answer: On O2, your number is at risk after 6 months with no chargeable activity. The original number isn't retained, and a reconnection fee may apply.
How long you have on O2
An O2 number you don't use won't last forever — here's the deadline that matters. On O2, the number is at risk after 6 months with no chargeable activity. Even when O2 reconnects you, your old number is gone — so don't rely on getting it back.
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 O2 number back?
You can reconnect by contacting O2 — but you're issued a NEW number, not your old one. The original number isn't retained, and a reconnection fee may apply. 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 O2 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 O2 recycles your number?
On O2, your number is at risk after 6 months with no chargeable activity. The original number isn't retained, and a reconnection fee may apply.
Can you get your O2 number back?
You can reconnect by contacting O2 — but you're issued a NEW number, not your old one. 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 O2 official Pay As You Go service terms. 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 O2 before relying on it. KeepSim is a personal reminder tool; it does not provide telecom service or keep numbers active on your behalf.