In the trade, transport and shipping sector, the Single Window (SW) concept has been evolved over time in a number of forms, reflecting respective policy, regulatory, market and technological regimes of the domain. A SW primarily addresses the need for efficient electronic transactions between governmental and business entities; however the SW service model adopted by the responsible authority and the offered SW system functionality differ; currently at least two distinct approaches are observed, namely a customs-centric SW approach, and a maritime and port centric approach. In all respective cases, the SW service model, the SW ownership model (public, private or Private-Public-Partnership), legal and regulatory aspects and the SW revenue model (free or with a fee) consist pertinent SW service design issues. Thus, different types of SW systems evolve in terms of offered service bundle, namely ship clearance, cargo import/export, or port clear-ance SWs, where often vested interests and policy choices dictate the dominance of one model implementation over the other. Modern ICT tools may significantly help to organize and improve the efficiency of a SW design and implementation process. In this paper, admissible development frameworks and methodologies are examined towards the efficient implementation of SW service models that are explained. Our analysis is based on experiences gained in the Norwegian SW national initiative (http://www.sintef.no/Projectweb/MIS/) and the EU eFreight project (http://www.efreightproject.eu/).