Objective Examine the associations of training volume and longest endurance run with (half‐)marathon performance and running‐related injuries (RRIs) in recreational runners. Materials and Methods During the preparation for and directly after the running event, 556 participants of a half marathon and 441 participants of a marathon completed three questionnaires on RRIs, average weekly training volume and the longest endurance run. With finish time, decline in pace during the running event and RRIs as dependent variables, linear and logistic regression analyses were performed to test the associations with weekly training volume and the longest endurance run. Results In half‐marathon runners, a high training volume (>32 km/wk) (β −4.19, 95% CI: −6.52;−1.85) and a long endurance run (>21 km) (β −3.87, 95% CI: −6.31;‐−1.44) were associated with a faster finish time, while a high training volume (β −1.81, 95% CI: −3.49;−0.12) and a long endurance run (β −1.89, 95% CI: −3.65;−0.12) were also related to less decline in pace. In marathon runners, a low training volume (<40 km/wk) was related to a slower finish time (β 6.33, 95% CI: 0.18;12.48) and a high training volume (>65 km/wk) to a faster finish time (β −14.09, 95% CI: −22.47;−5.72), while a longest endurance run of <25 km was associated with a slower finish time (β 13.44, 95% CI: 5.34;21.55). No associations between training characteristics and RRIs were identified. Conclusions Preparation for a (half‐)marathon with a relatively high training volume and long endurance runs associates with a faster finish time, but does not seem related to an increased injury risk.