Like other dog breeds, Korean Jindos begin their reproductive years after reaching sexual maturity. Sexual maturity is typically reached between six and twelve months of age in female Jindos between six and eighteen months in males. The exact moment when a dog reaches sexual maturity might vary from one canine to the next.

A female Jindo's ideal breeding age is conditional on her current state of health, her level of both mental and physical development, and the breeder's desired outcomes. Waiting until a female Jindo reaches full maturity, usually about two years of age, is a preferred method for many breeders. There are health hazards and potential problems during the processes of pregnancy and delivery associated with breeding females too early in their development.

When male Jindos achieve sexual maturity and exhibit the appropriate behavioral and physical characteristics of the breed, they may then be utilized for breeding. Responsible breeding procedures should be considered, and the male Jindo's health and temperament should be confirmed, before he is considered for mating