Short answer: On US Mobile, your number is at risk after about 90 days of non-renewal. On cancellation US Mobile may give your number to another customer without notice.
How long you have on US Mobile
That US Mobile SIM you forgot about can stop being yours sooner than you'd think. On US Mobile, the number is at risk after about 90 days of non-renewal. US Mobile is one of the few with an official paid “hold my number” option (Snooze).
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 US Mobile number back?
Or pay “Snooze” ($2.98 / 30 days) to hold your number indefinitely without a full plan. On cancellation US Mobile may give your number to another customer without notice. 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 US Mobile 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 US Mobile recycles your number?
On US Mobile, your number is at risk after about 90 days of non-renewal. On cancellation US Mobile may give your number to another customer without notice.
Can you get your US Mobile number back?
Or pay “Snooze” ($2.98 / 30 days) to hold your number indefinitely without a full plan. 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 US Mobile official 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 US Mobile before relying on it. KeepSim is a personal reminder tool; it does not provide telecom service or keep numbers active on your behalf.