Opportunistic use of spectrum is disclosed that allows a device access to a wireless local area network (WLAN) when necessary on a restricted frequency band and provides efficient scanning and switching of device communications to an unrestricted frequency band when channels become available in the unrestricted frequency band. A device operating in the network on the restricted frequency band may receive information on a channel set over a channel in the restricted frequency band. The channel set may be a subset of channels in the network and indicate network channels available for potential use in the unrestricted frequency band. The device may then only scan the subset of channels in the channel set to search for available channels in the unrestricted band. The channel set may be determined by the network based on the operation of the device in the coverage of the restricted frequency band.