A method for accessing a network in an electronic system and associated portable device are provided. The portable device includes; a transceiver, supporting a plurality of predetermined communication protocols; and a processor, configured to connect the portable device to a connectivity service device in an electronic system via the transceiver when the portable device enters a coverage region of the connectivity service device. The connectivity service device retrieves service information from a plurality of electronic devices that are connected to the connectivity service device, to build a service list. The processor retrieves the service list from the connectivity service device, and determines a service from the service list to be used for communicating with the plurality of the electronic devices.