Abstract: For the integration of national tsunami warning systems to large scale, ocean-wide warning infrastructures a specific protocol has been developed enabling system communication in a system-of-system environment. The proposed communication model incorporates requirements of UNESCO Intergovernmental Oceanic Commission tsunami programme to interlink national tsunami early warning systems. The model designed to be robust simple is based on existing interoperability standards. It uses the Common Alerting Protocol (CAP) for the exchange of official tsunami warning bulletins. Sensor measurements are communicated via markup languages of the Sensor Web Enablement (SWE) suite. Both communication products are embedded into an envelope carrying address information based on the Emergency Data Exchange Language Distribution Element (EDXL-DE). The research took place within the context of two European research projects. The reference implementation of the presented results was tested independently in deployments at two early warning centers. © 2012 ISCRAM.