Examining the differences between Iran and the Republic of Azerbaijan in the legal regime of the Caspian Sea from the perspective of international law

The collapse of Iran and the transformation of two Caspian water neighbors, Iran and Russia, and the addition of three other countries, Azerbaijan, Turkmenistan, and Kazakhstan, have caused border disputes between them. At the same time, the attitude of these countries has also changed towards the conditions of this water area and the methods of ownership and exploitation of it. Among the most important countries that have differences in this field are Iran and the Republic of Azerbaijan. Despite having historical commonalities, the two countries have a fundamental difference of opinion on issues related to the Caspian Sea from a legal point of view. Thus, this research intends to answer the question that what are the factors influencing the differences between Iran and the Republic of Azerbaijan in legal terms in the Caspian Sea? The hypothesis of the article has been answered by the descriptive-analytical method and the collection of library sources, that the different attitudes of the two countries regarding whether it is a sea or a lake, different attitudes towards the conventions of 1941 and 1920, the difference of attitude in determining the boundaries and differences in the issues of dividing common fields of energy and islands Artificial is one of the points of difference between the two countries. The findings of the research show that the continuation of the current approaches and their lack of peaceful resolution will hinder the convergence of the two countries in the field of water-energy cooperation.