When do Bernese Mountain Dogs calm down?

Bernese Mountain Dogs start to calm down and show signs of maturity around two to three years of age. By this time, they have usually reached their full size and physical development. During their puppy and adolescent stages, Bernese Mountain Dogs are typically more energetic, playful, and curious, and they might have higher activity levels and require more exercise and mental stimulation. As they mature, they become more settled, relaxed, and less hyperactive.