An experiment was conducted to assess the effect of NPK fertilizer (20: 20: 20), with control and two concentrations (250 mg/100 L and 500 mg/100 L), two distances (1 m and 2 m) in two different plantation sites, Hamata and Safaga at the shoreline of the Red sea. The average of growth parameters of Rhizophora mucronata seedlings (height, number of branches/plant, number of leaves/plant, fresh and dry weight/ plant) are determined, after three and six months of plantation. At the end of experiment, the photosynthetic pigments content (chlorophyll a, chlorophyll b and carotenoids) are determined in the seedlings in both the two sites and at different plantation distances. The data indicated that, most of growth parameters of R. mucronata seedlings were higher in Hamata locality compared with in Safaga locality. Fertilization by 500 mg/100 L NPK is essential for good and healthy growth of R. mucronata seedlings. Planting distance 2 × 2 m was more suitable for healthy growth of R. mucronata seedlings. The study showed successful propagation of R. mucronata in new sites about 500 km northward its natural distribution range on the Red Sea coast of Egypt.