The following services are supported for Transatel’s MVNOs and subscribers:
– VoLTE Roaming: Make calls on 4G/LTE on applicable partner networks
– SMSoIP: Send SMS via the 4G/LTE network on applicable partner networks

VoWiFi is not supported in roaming

The current list of partner networks is:

Network Name – Destination – PLMN
Taiwan Mobile – Taiwan – TWNPC
Telus – Canada – CANTS
Far EasTone – Taiwan -TWNFE
China Telecom – China – CHNDX
Telia Sverige AB – Sweden – SWETR
Telia Mobile – Denmark – DNKIA
Telia Estonia – Estonia – ESTEM
Telia Lithuania – Lithuania – LTUOM
Telia Norge – Norway – NORNC
Telia Finland – Finland – FINTF
JT (Jersey) Limited – Jersey – GBRJT
TIM – Italy – ITASI
Bell – Canada – CANBM
NTT DoCoMo – Japan – JPNDO

the technology is new – this list will grow as IMS roaming services are opened up with partner networks.

The handset must be attached to one of these networks for the services to work. There are more than one network in every country, and not all networks of every country are enabled (for now). If a subscriber is having difficulty making communications in a country, it may be advisable to manually select one of the above networks via the handset.

All services and charges will continue to function as usual. There are no additional surcharges for these services.

The availability of these services remain the same criteria as national IMS services
– compatible handset
– IMS (VoLTE/4G Calling) activated on the handset
– IMS provisioned
– LTE coverage

Yes, Hiya will be available with VoLTE roaming, provided that the host network’s IMS is compatible with the necessary Hiya parameters to support call identification services.