The ENVISION project provides an ENVIronmental Services Infrastructure with Ontologies that aims to support non ICT-skilled users in the process of semantic discovery and adaptive chaining and composition of environmental services. Innovations in ENVISION are: on-the-Web enabling and packaging of technologies for their use by non ICT-skilled users, support for migrating environmental models to be provided as models as a service (Maas), and the use of data streaming information for harvesting information for dynamic building of ontologies and adapting service execution.The ENVISION Environmental Decision Portal supports the creation of web-based applications enabled for dynamic discovery and visual service chaining. The ENVISION Ontology Infrastructure provides support for visual semantic annotation tools and multilingual ontology management. The ENVISION Execution Infrastructure comprises a semantic discovery catalogue and a semantic service mediator based on a generic semantic framework and adaptive service chaining with data-driven adaptability.Scenario requirements and pilots from the ENVISION user partners focus on landslide hazard assessment and environmental pollution (oil spills) decision support systems. The benefit of ENVISION for the wider community will be better accessibility to modelling tools using the Web and it will provide greater flexibility through improved connections to distributed sources of information.The technology partners contribute their technologies for semantic service discovery and chaining based on semantic annotations as a foundation for the infrastructure of ENVISION.The impact of the project is ensured through strong partner participation and leadership in relevant standardisation communities (e.g. INSPIRE, OGC, ISO/TC211, OMG and OASIS), in user communities like SEISnet and EuroGeoSurveys and through the development of open-source software and reference implementations supporting open standards.