Travel and tourism are potential areas for applying Web service technologies, especially with service integration of multiple travel information sources and tasks. It is required to support users dynamically and flexibly planning their trip plans which can be realized by various services. In this paper, we present a semantic method that automatically transforms high level trip plan templates into executable processes. A trip plan is defined by using OWL-T, a task ontology language, to capture userspsila travel requirements. Semantic technologies are used to map such trip templates into executable processes expressed in BPEL, a business process language. A prototype system was developed for illustration.