: In this paper we present our ongoing work in creating a semantic Web service composition and execution framework. The efforts described are undertaken in the context of the SATINE1 project that develops a semantic based interoperability platform for the travel industry. The proposed framework provides mechanisms and tools for both, visual orchestration of semantically well defined building blocks and the semantic lookup and invocation of concrete service instances that comply with user-specified constraints. As the core of our approach we introduce self-contained activity components that are created semiautomatically based on OWL-S service ontologies. By exposing a well-defined set of interfaces an activity component is being used and manipulated by appropriate tools throughout the whole composition and execution life-cycle, i.e. during visual modelling of the complex service, in the deployment phase and in the execution phase when being invoked by a workflow engine. 1 The SATINE Pro...