Tsunami buoys are not independent warning systems, there are singular measurement systems. For GITEWS, the buoy systems were developed for the verification of a tsunami in the open ocean. For the first time, modern GPS receivers and various, especially meteorological sensors were installed on the buoys themselves, so that a buoy itself is a measuring instrument. The buoys can be complemented by ocean bottom units; two development lines are available (OBU PACT). Buoy systems can be employed usefully and reliably in the Indian Ocean - as in the other world's oceans - if operation and maintenance can be assured technically, organizationally and financially.

The most important information for a rapid warning, namely the magnitude and fast localisation of an earthquake, cannot be delivered by buoy systems. At the beginning of the project buoy systems were included in the planning, because they belonged to the "classic" instrument pool of the existing tsunami warning systems. The buoys developed within GITEWS belong to the most advanced worldwide. In the course of the project it quickly turned out that the buoy information cannot be on hand in time for the quick warning necessary in Indonesia (5 minutes after the earthquake), however equivalent information can be obtained in the required short time span through the integration of land-based GPS as an innovative element. To at least deliver information within the first ten minutes of an earthquake, the buoys have to be very close to the earthquake zone and thus anchored close to the coast of Indonesia. The possibility of "vandalism" by fishermen who use the buoys to moor their vessels was, however, underestimated, as was the dense ship traffic near the coast.

Offshore instruments are particularly expensive to maintain. The calculation for the operational cost of the Indonesian system as a whole reveals that the maintenance and operation of the buoy systems alone (20 in total, of which 10 from Germany) costs as much as a comparable service for all of the approximately 280 instruments installed on land. Further examinations of cost and benefit took into account that maintenance is laborious, the buoy data usually comes too late for the first and most important warning and that a limited availability of the systems is to be expected due to vandalism. This led to the overall decision to no longer consider the buoy systems for early warning in Indonesia. Due to the development and expansion of the novel land-based measuring system the offshore buoys is no longer necessary for tsunami early warning in Indonesia.