The number of mobile terminals is continuously increasing in the world, although in many developed countries the market has saturated. Thus, the market can only grow if new service types are offered to the mobile terminals. One emerging technology that might make this possible is semantic web services. At the core of this technology are ontologies that are necessary for automatic discovery and composition of the services. In this paper we discuss how mobility affects the architectural considerations of semantic web service platform and particularly ontology management. We rely on reference architecture for Semantic Web Services in our work.