An approach is provided for reliably exchanging location service data over an unlicensed mobile access network operating with a cellular network. A request is processed for position location information of a terminal configured to operate with an unlicensed mobile access network that has connectivity with a radio communication network for providing a position location service. Data message specifying the position location information is generated, wherein the data message and the request are generated according to a signaling protocol that is compatible with the unlicensed mobile access network. Reliable delivery of the data message is provided by a transport layer protocol.