• By sending an USSD request
• By sending an SMS request
• By calling 1633 (+65 68201633^{^} when you are travelling overseas)

To De-activate: Dial *100# and SEND.
To Re-activate: Dial *101# and SEND.

To De-activate: SMS <DEACTIVATE> to 2828 and SEND.
To Re-activate: SMS <ACTIVATE> to 2828 and SEND.

Disclaimers:

1. Missed Call Alerts will not be sent if the missed call was made from payphones, PABX (Hunting lines) or lines with Caller Number-Non-Display or if the network operator you are roaming on charges for receiving SMS.
2. Maximum of Missed Call Alerts per person per day is 20.
3. For phone switched off or not within network coverage range scenarios, Missed Call Alerts will capture up to 9 missed call numbers (sent within 3 SMS) for the first 24 hours your phone was switched off/out of coverage.
4. Should you decide to deactivate this free service when you are overseas, you may wish to send the Deactivation request via USSD as it is free of charge. However, USSD requests are suppoted by certain overseas operators only. Please check list of supported overseas operators/destinations here.
5. ^If the overseas operator that you are roaming with does not support USSD requests, you can still deactivate this free service by sending an SMS request or by calling +65 68201633. However, please note that the overseas operator’s operators' respective roaming SMS charges or outgoing roaming airtime charges will apply if you are activating or re-activating via SMS.