Background: Supplementing β-alanine (BA) improves exercise performance in efforts that are highly dependent on anaerobic glycolysis. As it has not yet been established whether it relates to climbing, the current study aimed to investigate the effects of BA on climbing-specific performance. Methods: Fifteen elite climbers performed intermittent high-force high-velocity campus board exercise, and two bouldering traverses, hard and easy. They ingested 4.0 g·d−1 BA or placebo for four weeks in a double-blind, pre/post experimental design. Results: In the campus board trial, ANOVA revealed a tendency toward significance (p = 0.066). Post hoc analysis revealed that there was a significant (p = 0.002) and “large” (d = 1.55) increase in the total number of “slaps” in the BA group. No significant supplementation × group interaction was found in “hard” traverse and a significant interaction for mean changes in number of moves (p = 0.025) and in time to failure (p = 0.044) on an “easy” traverse. Post hoc analysis revealed that only the BA group significantly improved from baseline in number of moves (+9.5) and time to failure (+32 s). Effect sizes were d = 1.73 and d = 1.44, respectively. Conclusions: Four weeks of BA supplementation can improve performance during continuous climbing lasting about 1 min and repeated bouts of upper body campus-like movements. However, it failed to enhance climbing of a shorter duration.