Every day thousands of ships carry millions of tons of cargo worldwide. In complex logistics chains, minor decisions may easily have major consequences. The shipping industry suffers from a lack of shared data between ships and ports, which could lead to monetary loss when ships are delayed, fuel burned and suboptimal routes are chosen. Operations in the maritime industry are characterized by infrequent interaction among an extensive number of actors. In many other industries, close partnerships have stimulated systems integration and general standardization of information exchange. In shipping, however, this has yet to happen. Sea Traffic Management, STM, is part of the solution! STM establishes a global maritime digital infrastructure where standard messages can be sent and received. Interoperability is achieved by specifying not only WHAT format the data should have but also HOW the exchange should be done. When actors follow this design principle they can connect seamlessly even on their first encounter. Shipping is often a series of first-occasion encounters, as ships visit new terminals and ports most of the time. Data exchange among port actors can cut waiting times during port calls and assist in achieving just-in-time arrivals. In STM, information owners select the partners with whom they wish share data, thus avoiding business sensitivity issues. The goal of the STM Validation Project was to develop and validate the infrastructure and the services using it, and to verify the functions and benefits. The benefits predicted in the previous projects defining and designing the STM concept include: common situational awareness among ships and shore actors, reduced administrative burden, green steaming and just-in-time operations. The STM Validation project set up three test-beds. One test-bed was located in Northern Europe and another in the Mediterranean Sea. Apart from these operational test-beds, the European Maritime Simulator Network (EMSN) was used to validate complex cases involving many ships. EMSN tests using 30 manned bridges supplied data on the behaviour of mariners and to compile their feedback on STM. The test-beds were supported by the development of a maritime digital infrastructure. The validation of the port functions took place in parallel with current operations, whereas the ships and shore centres implemented services, many of which will remain operational after the project. Examples of functions and services include winter navigation services in the Northern Baltic Sea, enhanced monitoring in the Strait of Gibraltar, port arrival synchronization in Limassol, Search and Rescue (SAR) and ship-to-ship route exchange among 311 ships wherever they meet around the world.