By Act 66/07 the Dominican Republic (DR) proclaimed its archipelagic status and defined the geographical coordinates for the drawing of archipelagic baselines joining the outermost points of its archipelago. It further determined the rights exercised by third states in the enclosed waters and the airspace above them. On the basis of this new status, the Dominican Republic set out anew the coordinates for the outer limit of its Exclusive Economic Zone (EEZ). This article assesses the provisions of this Act in the light of international law. Apart from the question of whether the archipelagic claim of the DR is valid, this article examines two further claims raised by this Act, namely the restrictions upon the right of innocent passage of vessels carrying ultra-hazardous cargos and the assertion of rights over shipwrecks located in the EEZ. It finally assesses this state practice within the framework of similar state practice at the regional and international levels, and assesses its implications for new developments in international law of the sea.