From the perspective of law enforcement and other professions, covert visual surveillance can be an effective and necessary tool for performing tasks such as investigating crimes, fighting terrorism, and surveillance of suspicious individuals or groups. The relevance of covert visual surveillance depends on the context and situation. The research aims to assess the established techniques and modern methods of covert visual surveillance, as well as the means used to fulfil its tasks from the legal perspective. The study uses comparative legal, historical, and legal, logical, and legal methods, systemic and structural analysis, as well as methods of logic (analysis, synthesis, induction, deduction, analogy, comparison, and generalisation). The identification of specific techniques and means of covert visual surveillance allowed the author to formulate a legal assessment of the use of each of them in different conditions and by different subjects. Based on the results of the research, the author provides a legal description of various types of surveillance, including specific techniques for placing observers in space concerning various objects: movable and immovable; persons, objects, and certain places. The author assesses the legality of the use of technical means used during surveillance, as well as the means of ensuring its secrecy. The conditions for the legitimacy of the use of specific groups of techniques and means for conducting visual surveillance by various subjects are determined. It is argued that the use by private law entities of mobile surveillance techniques for monitoring a person identified by them is unlawful and will indicate the illegal collection of confidential information about them, committed by a group of persons by prior conspiracy. The practical value of the research lies in the possibility of direct use of its results by representatives of law enforcement agencies and other professions to choose acceptable (lawful) methods and means of conducting covert visual surveillance and avoid the use of unacceptable (unlawful) ones