Environmental issues have been widely promoted during the last four decades through both international instruments and countries’ domestic laws. Simultaneously, coastal zones have become more relevant on national agendas, and sectoral approaches to management of coastal zones have started to be replaced by more integrated approaches. Despite this, at the international level, only Agenda 21 has included ICZM as a core issue. This paper analyses, at the national level, the cases of Colombia and Cuba in respect of ICZM implementation and international instruments. Authors concluded that each country develops its own domestic law related to coastal issues, trying to fulfill its obligations under a variety of multilateral environmental agreements, but failing to take an integrated approach to implementing commitments under different agreements. At the same time, the relationship between domestic ICZM laws and relevant international agreements is not clear. As a result, international instruments relating to the marine environment are not, at present, effectively supporting domestic implementation of ICZM.