Embodiments of the present invention address deficiencies of the art in respect to navigation in GPS-enabled mobile computing devices and provide a novel and non-obvious method, system and computer program product for location-based tsunami alerting navigational instructions in mobile computing devices. In an embodiment of the invention, a location-based tsunami alerting data processing system can be provided. The system can include a central processing unit coupled with a memory component, and a visual display along with location-based navigation logic that is enabled to compute a geographic zone of danger resulting from a tsunami, identify a geographic location for a mobile computing device corresponding to a subscriber, and render a set of personalized navigational instructions in the mobile computing device responsive to a determination that the subscriber is located in the geographic zone of danger.