This work aims to determine the best substrate preparation and conversion coatings that may enhance the anti-corrosive performance of alumina film/stainless steel substrate systems in Ringer's solution. Boehmite, silica, silica/boehmite, and boehmite/silica conversion coatings were deposited on sanded or sandblasted 304L stainless steel samples, and the best results were further covered with alumina film for a long-time exposure evaluation. The best anti-corrosive performances for each substrate preparation were observed for the sandblasted sample covered with silica/boehmite conversion coating (JSB500) and the sanded sample covered with silica (LS500), which showed the highest global resistance (R g ) values (828 Ω.cm 2 and 1837 Ω.cm 2 , respectively) and the smallest values of global capacitance, C g (2.19 X 10 -6 F.cm -2 and 3.37 X 10 -9 F.cm -2 , respectively). After covering with the alumina film and evaluating for 216 h in the corrosive medium, it was noted an increase in the R g values for both systems (JSBA500 and LSBA500), likely due to the presence of a corrosion products layer. The presence of iron oxides in these conversion coatings led to a more stable alumina film. Comparing the selected coating systems, the LSBA500 exhibited an improved performance, reaching an increase of 85% in R g and a decrease of 94% in C g .