Short answer: Complete at least one chargeable activity every 180 days. Three says a disconnected PAYG number cannot be reconnected, so do not rely on a recovery window.
Open the SIM expiry calculator for a sourced deadline
What Three counts as chargeable activity
Three's PAYG support page lists these examples:
- buying a top-up, Data Pack or Add-on;
- making a call, sending a text or using mobile data on Three's mobile network, not Wi-Fi;
- using an allowance from top-up credit, a Data Pack or an Add-on.
Receiving a message or using WhatsApp on Wi-Fi is not on that list. Choose an action that creates a visible usage or purchase record and complete it before the 180-day point.
Timeline and warning
| Point | Result |
|---|---|
| Before 180 days | Complete a qualifying chargeable activity |
| 180 days without one | Three may disconnect the PAYG number |
| After disconnection | SIM stops working and the number is lost |
Three may send a warning, but its public support page does not give a guaranteed notice period. A warning text is useful confirmation, not a scheduling system.
Can Three reconnect the number?
Three's answer is no. It directs a disconnected customer to order a new PAYG SIM, use Live Chat, or visit a store. A separate page notes that a recently closed account may still qualify for a PAC, but that is a number-transfer process and should not be treated as guaranteed reactivation.
Compare UK PAYG policies, read what inactivity does to a prepaid number, or return to the UK carrier section.
Log the chargeable action, not just a calendar date
KeepSim can remind you and record when you completed the action. It cannot confirm Three's billing record or reconnect a lost number.
Get KeepSim on the App StoreOfficial source
- Three UK: Pay As You Go support, reviewed 2026-08-01.
- 2026-08-01: added Three's complete current activity list and clarified that disconnection cannot be reversed.
KeepSim is not affiliated with Three UK. Check My3 after the action and keep the confirmation.