The present article examines if the principle of freedom of the high seas as formulated by Hugo de Groot still plays a significant role in international law. The article starts from an analysis of De Groot's ideas on the law of the sea and then turns to the freedom of the high seas in the modern law of the sea. In both cases, the legal framework is assessed against the background of the activities that require(d) regulation. Freedom of the high seas, although it has lost ground to other ordering principles, remains significant at the level of principles. However, at the level of designing an effective regime for current problems in oceans management, which to a large extent are caused by deficiencies in the enforcement scheme implicit in freedom of the high seas, the writings of De Groot, in whose time those activities did not require any significant measure of international coordination and cooperation, offer little assistance.