Distance running offers many health benefits, yet injuries are common. In long-distance runners (>20 km/week), a previous running-related injury (RRI) is the strongest predictor of injury1. In females, menstrual dysfunction and low bone mineral density (BMD) increases bone stress injury (BSI) risk2. A recent meta-analysis of diet-related risk factors found lower total energy and fat intakes in injured female runners, and a lower fibre intake in both sexes combined with a BSI3. Of the four studies contributing to these findings, all involved younger trained or highly trained athletes, with only one including females up to 53 years. Older runners may be at increased risk due to age-related physiological changes and nutrient deficiencies, but prospective studies are lacking. This study aimed to evaluate the relationship between bone health, diet, and RRI in masters distance runners. Male and female masters athletes (≥35 years) running ≥30 km/week enrolled in a 6-month prospective study. Baseline measures included demographics, diet (energy, macro- and micronutrients), and BMD (total body and site-specific). Dietary intake was compared to Australian nutrient reference values or sports recommendations. Weekly running mileage and injury occurrence were tracked for six months. Analyses were conducted for the whole cohort and by sex. Of 100 runners (n = 56 male) completing the study, 26 sustained a soft tissue injury (with one combined soft tissue and BSI). Injured runners (both sexes combined) had lower dual femoral neck BMD (Hedge’s g = -0.51, p = 0.028), Z-score (Hedge’s g = -0.52, p = 0.032), and T-score (Hedge’s g = 0.40, p = 0.040) compared to uninjured runners. Injured females had lower dual femoral neck BMD (Hedge’s g = -0.64, p = 0.049) compared to uninjured females, and females with whole-body T-score <-1 had higher injury risk (OR = 6.4, p = 0.030). Few runners met their estimated energy requirements (24% females, 29% of males), with no difference in intake between injured and uninjured runners. Similarly, no significant relationships were observed for macronutrients. Males not meeting calcium recommendations had higher injury risk (OR = 4.0, p = 0.03). Females not meeting iron recommendations had lower injury risk (OR = 0.21, p = 0.038). Findings suggest bone health may influence soft tissue injury risk in masters distance runners, as shown by sex-specific associations between BMD and injury. No associations for energy and macronutrients may reflect overall inadequate intake. Inadequate calcium intake in males may impair soft tissue integrity and repair, increasing injury risk. The protective effect of low iron intake in females may relate to poor overall intake or use of age-based recommendations that overlook menstrual status. Larger, long-term studies using age-appropriate assessments are warranted.