This paper describes the proof-of-concept demonstrator implemented as part of the project Enhanced Situational Awareness to Improve Maritime Safety in the Baltic (BONUS ESABALT). The demonstrator represents the system as used in different classes of vessels including leisure craft (small boats), larger ships, and authority vessels. Various validation scenarios are implemented to demonstrate the system functionality, for example application of ESABALT to aid in recovery operations after an oil spill, rerouting in the presence of significant sea-ice, aiding vessel navigation in case of a GNSS interference event, and situations where multiple ships are in distress. The demonstrator is implemented on a laptop computer and using the FURUNO FFSC-200 software environment, FURUNO Finland FICE-100 ice radar and FOIL-200 oil radar, live ship data from AIS receivers, dashboard camera, and the FURUNO Navisimu simulator environment. The simulated data include AIS tracks, radar echo and tracks, and small boat tracks. The paper also describes the implementation challenges, quality of service factors, and results of the economic and non-economic viability analysis of the proposed ESABALT system for potential full-implementation in the future. This study shows that the system would be cost-effective and the benefits to international cooperation, maritime safety, and environmental monitoring would outweigh the management costs necessary to sustain it.