The increasing migration of population in the world is one of the urgent international problems. States make efforts to counter the illegal migration and to help people seeking asylum. This problem is the most challenging to tackle in the sea. The article reveals the contents of international cooperation and the role of international law in this field. The specific features of tackling illegal migration are analyzed within the various marine spaces: in inland waters, in the territorial sea and in the open sea. The issues of international cooperation on suffering refugees and other migrants in danger on the sea have been studied as well. International legal and organizational issues facing the world community are introduced and their separate solutions are offered. In the authors' opinion, the activities of states regarding migrants should be carried out in compliance with their legal status and particular situation. In any case, the migrants' status must be defined not on the sea but on the shore. If some people are in danger, they must be helped notwithstanding the legal status of the persons being rescued. Measures of criminal liability and other measures according to the legislation of states and international commitments must be applied to illegal migration organizers. It is important that the rules of international law, international organizations and international bodies recommendations that deal with the problems of migration should be carried out at the national level by means of upgrading related laws. It is also important to work out and to upgrade the subordinate regulatory legal acts concerning the questions of illegal sea migration counteraction, measures taken towards refugees and other asylum seekers, being present on board of the ships in distress. Accordingly, the issue is to be solved as to the attitude of states towards the migrants on board of the watercraft that do not comply with the seafaring security requirements that means that they are potentially in danger.