AbstractThree seaweeds (Halimeda tuna,Codium bursaandCystoseira barbata) and one seagrass (Cymodocea nodosa) were collected from the Coast of Montenegro, Gulf of Boka Kotorska and their chemical analysis was performed. In seagrassC. nodosa, three phenolic compounds were identified (diosmetin 7‐sulfate, caftaric and coutaric acid). The content ofβ‐glucan, fatty acids, sterols and micro‐ and macro‐elements were investigated among all samples. The highest content ofβ‐glucan was detected inC. nodosaseagrass (13.04±0.42 g/100 g). The highest polyunsaturated fatty acids (PUFAs) level was reported inC. barbata, the brown alga (7.157 mg/g), which also had the significant sterol content (fucosterol, 21.76±0.1 μg/g). Green algae,C. bursaandH. tuna, showed the highest level of sterols (β‐sitosterol, 95.21±0.16 μg/g and 73.90±0.08 μg/g, respectively).H. tunahad the highest content of calcium (Ca) in amount of 55125 μg/g. InC. bursa,C. barbataandC. nodosa, the Na/K ratio was low (0.43, 0.46 and 0.69, respectively).