Background: The aim of the study was to assess the effect of climbing on static and dynamic balance and to determine the usefulness of such training in supporting the fitness of young adults with mild and moderate intellectual disabilities. Method: The study involved 47 men and 21 women aged 18-25 years. The experimental group participated in classes on an artificial climbing wall for 15 weeks. At that time, the control group did not participate in any organised sports activities. The balance was assessed twice using tests: a bench walk, a functional reach, a single leg stance with the eyes open and closed, and a BTS P-WALK baroresistive platform. Results: In the experimental group there were improvements in functional reach test by 7.79 cm (p < 0.001), balance walk test by 0.47 pts (p = 0.003), improvements in frontal and sagittal plane stability, and tilting area in the closed eyes test. The changes that were observed in the control group were not statistically significant. Conclusions: Climbing activities can be part of a rehabilitation program to improve balance.