Environmental policy-making in West and Central Africa, with implications for the region's ports, is usually dominated by state actors that also represent the nation-states at regional inter-governmental co-operation. The ports share common and transboundary environmental problems, but fall under diverse political and decentralisation systems. Also, in spite of regional inter-governmental co-operation there is disagreement between regional environmental policies and those for the ports at sub-national level. The port authorities are largely absent in environmental negotiations with outcomes ignoring their contributions. However, institutional reform of the ports from the year 2000 onwards has seen the port authorities gaining greater autonomy as public non-state actors and beginning to involve in environmental policy-making. This paper seeks to understand how environmental policy-making and governance is transforming in West and Central African ports. By combining the policy arrangement approach, the main analytical tool for the paper, with the concept of regional convergence, interaction processes among key actors involved in port environmental policy-making in West and Central Africa are studied. The study finds a developing innovation of joint environmental policy-making arrangement in which West and Central African port authorities, from sub-national level, are engaging directly with regional inter-governmental and Environmental Non-Governmental Organisation actors. The developing innovation by-passes institutionalised state-led environmental policy-making arrangements, with the potential for transforming environmental governance of West and Central African ports. It is concluded that non-state actors, when given flexible manoeuvring, can be innovative in overcoming diverse statist political dynamics in dealing coherently with transboundary environmental issues within a territorial region. However, state actors remain key as linking pins in transboundary environmental policy and governance.