The purpose of this study was to investigate if the impact attenuation properties of ice hockey helmets change after being used for one season in a professional ice hockey league. Eighteen helmets from a male team and 10 helmets from a female team were compared to 13 new helmets. Every helmet was impact tested three times for two impact locations, side and front. The median peak linear acceleration for all front impacts were significantly higher (p < 0.05) for the helmets from the female team compared to the helmets from the male team. Compared to the new helmets, both men’s and women’s helmets had significantly lower median peak angular acceleration (p < 0.01) and peak angular velocity (p< 0.001). For side impacts, the women’s helmets had significantly higher peak linear acceleration compared to the men’s and new helmets (p < 0.001). Both men’s and women’s helmets had significantly higher peak angular acceleration compared to the new helmets (p < 0.001), and women’s helmets also had significantly higher peak angular acceleration compared to men’s helmets. Compared to men’s and new helmets, the results show that women’s helmets have worse impact attenuation properties after one season. However, all used helmets satisfied the passing threshold for test standards and the differences in calculated injury risk were small. This information may assist in establishing recommendations for the expected lifetime usage for ice hockey helmets and support manufacturers to develop safer ice hockey helmets.