GEOSS has the objective to continuously monitor the state of the earth in order to increase knowledge and understanding of our planet and its processes. Being a system of system, GEOSS has to master the challenge of integrating heterogeneous systems across institutional and political boundaries. Timely delivery of earth observation data is a key aspect in identifying potential natural and human threats, such as tornados, tsunamis, wild fires, or algae blooms. The third workshop of the Sensor Web series invites you to come to Japan to present your current activities and opinions in the context of Sensor Web or Sensor Network applications. Building on the achievements of the first two workshops (see reports on: http://www.sensorweb-alliance.org), this workshop continues the very successful discussions and knowledge exchange about interoperable sensor networks.