Magnetic skyrmions, which are topologically protected particle-like spin textures, exhibit Brownian motion at ambient temperatures in a ferromagnetic thin film. The potential applications of a skyrmions’ diffusive motion to the ultra-low energy stochastic and Brownian computation make research on its thermal dynamics necessary. Herein we experimentally demonstrate the mobility anomaly of the diffusion coefficients in one-dimensional diffusion processes. In addition, we observed a chiral property in the velocity–position correlation functions. The results are discussed in the context of Brownian motion in the shallow potential fluctuations. The data indicate the importance of the chiral property of skyrmions in Brownian motion.