The aim of this research work is to investigate the seawater resistance of concrete incorporating silica fume (SF), ground granulated blast furnace slag (GGBS) and metakaolin (MK) as an addition to cement in binary and ternary combinations. Permeability of different mixtures was measured. Strength deterioration ratios (SDR) were determined after 3, 6 and 12 months of exposure to synthetic seawater. Chloride ion concentrations (chloride ingress) at the surface layer and at the core of tested specimens were determined after 6 and 12 months of exposure. The mineralogical compositions of all mixtures before exposure and after exposure to synthetic seawater for 12 months at the surface layer and at the core of tested specimens were investigated by X-ray diffraction (XRD). The results indicate that the binary combination of cement-SF proves to be the most effective pozzolana to resist seawater attack. The ternary combination of cement-SF-MK came in the second place. The ternary combination of cement-SF-GGBS came in the third place. The binary combination of cement-MK came in the fourth place. The binary combination of cement-GGBS came in the fifth place. The ternary combination of cement-MK-GGBS came in the sixth place. Finally pure cement came in the last place.