This studies discuss the synergistic effects of titanium dioxide (TiO2) and zinc borate on thermal stability and water resistance of intumescent fire retardant coatings. TiO2 in association with a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine/ zinc borate (APP-EG-MEL-ZB) was introduced to epoxy based coatings to improve the fire resistance. The influences of TiO2 on the properties of the coatings were investigated in detail by using Bunsen burner fire test, thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM) and water immersion test. Bunsen burner test revealed that incorporation of titanium dioxide in intumescent formulation reduced the steel substrate temperature from 240 °C to 116 °C. The TGA results proved that addition of TiO2 could enhance the anti-oxidation of the char layers and increase the residue weights of the coatings. The FESEM images demonstrated that addition of TiO2 could improve the foam structure of the char residue. Sea water resistance test demonstrated that the optimum mass age of TiO2 (6) exhibited great synergism with natural anti-corrosion agent, zinc borate, and improved corrosion resistance performance of intumescent coating formulations. © 2017 Trans Tech Publications, Switzerland.