VoLTE Roaming Service

Voice over LTE (VoLTE) can now be used outside Hong Kong. VoLTE Roaming Service allow 1O1O customer connects voice calls through overseas partner’s 4G LTE network while roaming. We will extend our VoLTE Roaming Service coverage and let you start experience the speedy VoLTE call connection, try to provide the best roaming service and support you every step around the world.


How to dial

No matter you are connecting with VoLTE Roaming Service or traditional roaming voice call, please use the following dialing method:

<+> + <country code> + <area code> + <phone number>

Example: When you want to call back HK while roaming, simple input “+852 <phone number>
A free of charge voice reminder for how to dial will be played if you are using VoLTE Roaming Service


To enjoy VoLTE Roaming Service, you must:

  • Enable VoLTE service
  • Enable IDD and Roaming service
  • Use compatible device, updated to corresponding latest designated software version.
  • Connect to partner’s network which has enabled VoLTE Roaming Service

There is no additional charge for VoLTE Roaming Service, which is the same as current standard roaming voice call.

VoLTE Roaming Service call will not be counted as your roaming data usage. All VoLTE Roaming Service calls will be calculated in minute and rounded up to the nearest minutes.

Yes, once you ensure the VoLTE option is turn on (if applicable), you can make VoLTE Roaming Service call with data roaming turn off in your handset menu.

Call the 1O1O Product Hotline on 2988 1010 or visit a 1O1O Center for details.

1. VoLTE roaming service allow 1O1O customer connects voice calls through overseas partner’s 4G LTE network while roaming (“VoLTE Roaming Service”)
2. VoLTE Roaming Service is only applicable to 1O1O postpaid service plan customers who are enabled to access to 1O1O VoLTE service. Customer must register and activate IDD, Roaming, and use designated compatible device with specified system version in order to use VoLTE Roaming Service in designated areas with designated networks. For details, please visit https://www.1010.com.hk/en/business_roaming_mass
3. VoLTE Roaming Service may not completely cover all locations within the periphery, depending on performance of 4G LTE networks run by local operators. Roaming service will automatically switch to 2/3G, or other technologies, in locations not covered by a LTE network.
4. Usage will be calculated on a per minute basis. Any usage of less than one minute will be counted as one minute.
5. VoLTE Roaming Service will be available first to personal account customers of 1O1O. JOC/1C2N customers have not yet been available. We would timely update at our webpage. If customer has not registered for IDD and roaming services or has already applied for “barring of IDD or roaming voice service”, upon request on using VoLTE Roaming Service, it represents the customer agrees to activate IDD and roaming service and agree to “un-bar IDD and roaming voice service”.
6. In case of any dispute, the decision of CSL Mobile Limited is final.
7. In the event of any discrepancies between Chinese and English versions, the English version shall prevail.