The sport of climbing and the ability level of the top climbers have evolved substantially over the past few decades. The purpose of the present study was therefore to determine the importance of different physiological determinants of climbing performance. The study was performed in a cross-sectional design with 26 climbers at an advanced level and 16 climbers at an elite level. Muscle thickness of the finger flexors—Flexor Digitorum Profondus (FDP) and Flexor Digitorum Superficialis (FDS), hip/lower extremity mobility, maximal isometric finger strength and rate of force development (RFD), and climbing specific endurance were assessed in climbing specific tests. The results showed that the elite group performed significantly better than the advanced group in all tested variables, adjusted for sex. Multiple regression analysis did however reveal that maximal average finger strength and RFD, relative to body mass, were the strongest independent performance-determining factors, and further that these factors are influenced by the muscle thickness of the finger flexors. We conclude that the elite-group of climbers perform at a higher level than the advanced-group of climbers in all measured climbing specific variables, but finger flexor strength and RFD seems to be the most important determinants of climbing performance. A data file containing the entire dataset (Data_sheet_climbing_performance.csv) and a a ReadMe-file (Readme_physiological_determinants_climbing.txt) is included