The topic of this thesis is determination of durability properties of concrete in the marine environment. This paper is divided into theoretical part and experimental work. The introductory part deals with the issue of concrete durability. The next chapter explains characteristics of the marine environment and its impact on concrete. Furthermore, the of chlorides in concrete and the mechanisms of transport of chlorides in concrete with special emphasis on diffusion are described. Also, the process of armature corrosion and formation of passive layer on steel surface are described in order to better understand the chlorides and carbon dioxide in steel armature corrosion. The processes of degradation concrete and armature caused by chlorides from the sea are described, as well as the process of carbonation of concrete. Standards, procedures and apparatus for determining the resistance of concrete to the penetration of chlorides and the passage of gases through porous structure arediscussed. Finally, in the experimental work, the properties of durability, more specifically gas permeability and chloride diffusion on 23 samples of concrete that be used in the construction of the future ferry port were examined, and the test results analyzed.