Extrapulmonary nontuberculous mycobacteria (NTM) infections contribute to morbidity and mortality worldwide. However, studies about extrapulmonary NTM infections have been limited. Therefore, we aim to describe the diversity of extrapulmonary NTM infections and identify predictors for species. Information regarding diversity of NTM isolates, antimicrobial susceptibility testing, treatment regimens, and outcomes were collected from four tertiary care centers in South Korea. Comparisons were made between patients with rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM) infections. A total of 117 patients (46 males vs. 71 females) were included. Skin and soft tissue infections (SSTIs) predominated (34.2%), followed by bone and joint infections (28.2%). In SSTIs, RGM species were predominantly identified (26/28, 92.9%), whereas SGM species were mainly identified in bone and joint infections (18/26, 69.2%), and the difference of isolated sites was verified by a post hoc test (p < 0.001). Multivariable regression analysis revealed that male sex (vs. female sex; OR 5.30, CI 1.35–24.26, p = 0.020) and bone and joint infections (vs. SSTIs; OR 18.10, CI 3.28–157.07, p = 0.002) were predictors of SGM infections, whereas the opposite was observed for RGM infections. Bone and joint infections and male sex were predictors for SGM infections, whereas SSTIs and female sex were predictors for RGM infections.