This thesis studies the intersection between the law of the sea and the application of United Nations Security Council resolutions. Through its resolutions under Chapter VII of the Charter of the United Nations, the Security Council authorizes or compels Member States to act in a way and in doing so, it may alter some of the law of the sea norms, creating a lex specialis for the sea. In the context of this thesis, the lex generalis is the law of the sea in toto, not only the United Nations Convention on the Law of the Sea, and the lex specialis encompasses the Security Council resolutions. To test the law of the sea vis-à-vis the Security Council resolutions, its action has been studied in different situations as in collective security, peacekeeping operations, piracy and robbery, migrants at sea and the transport of weapons of mass destruction. The assumption that the Security Council creates a lex specialis was verified as the content of the resolutions regulates directly or indirectly the general law of the sea in a different sense. Therefore, out of two norms, only one lex must be applied in that specific situation and that is the lex specialis, the one that the Security Council has decided to apply in specific circumstances.