In this paper, sea water, instead of tap water, was used in mixing and curing the concrete. The experimental work consisted of 48 cubic, with 100 mm side length, plus 48 cylinder, with diameter of 100 mm and height of 200 mm. The main parameters were water type, either sea or fresh, and the curing period. The concrete mix were divided into four groups. The first was casted and cured using fresh water (FF) while the second was made from fresh and cured using sea water (FS). The third was casted and cured using sea water (SS) while the last was casted from sea water and cured by fresh water (SF). Specimens of four groups were tested at 7, 15, 28 and 90 days. The compression and splitting tensile tests were investigated to estimate the tensile /compressive strength of the concrete. It was showed that the compressive strength of three groups (FS, SS and SF) increased with concrete age until 28 days then it decreased. On the contrary, the compressive strength of FF increased until 90 days. Compressive strength of SS was 46.9, 64, 59.39 and 19.1 % higher than that of FF at ages 7, 15, 28 and 90 days, respectively. Patterns of the failure did not modify with replacing fresh water with sea water in the mix. The tensile response over the time improved until 90 days for FF group only while tensile strength of other groups increased until 28 days then it decreased. Enhancement rates in the tensile strength of SS were 46.51, 41.3, 75.89 and 54.11 % referenced to FF at ages 7, 15, 28 and 90 days, respectively.