A UE can enable a VoWIFI service, receive hidden SSID information, and register with a core network via a RAN. The UE can monitor a first signal strength of a first signal from the RAN. The UE can scan for a second signal from a WLAN, and when found, can measure a second signal strength of the second signal. The UE can determine whether the first signal strength is at or below a first threshold. If so, and if the WLAN is untrusted, the UE can probe it with the hidden SSID information. If the untrusted WLAN responds, the UE can send an access request to an untrusted WLAN access point. The UE can receive, via the untrusted WLAN access point, an authentication challenge from an ePDG. If the UE passes the authentication challenge, the UE can register with the core network via the untrusted WLAN and the ePDG.