Epidemiological evidence has shown that prolonged exposure to the pool water is associated with enamel erosion. Although mouthguard and fluoride mouth rinses are recommended for protecting the teeth from damage by acids, the supporting evidence has been scarcely documented. Objective: To assess the effect of a mouthguard and fluoride mouth rinses on surface hardness of dental enamel after exposure to chlorinated water. Methods: In vitro experimental design study, 44 human premolar teeth were mesiodistally separated into buccal and lingual parts. Enamel slabs from each tooth were randomly allocated into the study group (enamel slabs with mouthguard) and the control group (enamel slabs without mouthguard). Both groups were immersed in chlorinated water at pH 3 for 2 hours, and then immersed in 0.05 NaF mouth rinses for 1 minute. Enamel microhardness was assessed before and after immersion using Vickers microhardness tester. Another three human premolar teeth were prepared to examine the enamel appearance before and after immersion using scanning electron microscope (SEM). Results: The mean Vickers microhardness number (VHN) of the control group at baseline was 345.48±29; and was 291.92±36 after immersion; and the mean VHN difference, (before and after immersion), was 53.55±4. The mean VHN of the study group at baseline was 341.19±26; and was 346.12± 37 after immersion; and the mean VHN difference was -4.48±4. Using t-test, the results showed statistically significant in mean VHN difference, between the control group and the study group (p<0.001). SEM revealed honeycomb-like etched patterns on enamel surface of all specimens in the control group but not in the study group. Conclusions: Exposure to swimming pool water at low pH for long duration leads to dental erosion and the use of mouthguard and fluoride mouth rinses can protect dental erosion, with respect to surface hardness and appearance.