From Bulbapedia, the community-driven Pokémon encyclopedia.
A Pokémon journey is a quest undertaken by a Pokémon Trainer to learn to live and work with Pokémon. In the anime, a person's Pokémon journey can begin as early as the age of 10, when they can first legally apply for a Pokémon Trainer's license. It is at this point that a Pokémon Professor can give them a starter Pokémon native to their own region, though many people befriend or are given other Pokémon prior to being legally able to be Trainers.
Pokémon Trainers may choose to journey alone or with friends and people they meet along the way. On their journey, Trainers can stay at a Pokémon Center free of charge, where their Pokémon can be healed by the resident nurse.
In the games
The core series games chronicle the Pokémon journey of an individual Trainer, the player, across a region that is dependent on the game being played. The player will often begin a journey around the same time as one or more rivals, whom they will meet at various points through their travels, and may battle against or along with them. This journey is typically focused on defeating the region's eight Pokémon Gyms, defeating the Elite Four, and becoming the Champion, though there are often sidequests along the way. A villainous team will always show up during the journey to impede the player's progress, and often, after the Pokémon League has been conquered, several post-League areas are available to continue the journey.
While sending children alone on a Pokémon journey is a normal part of life in the Pokémon world, many mothers remain understandably hesitant at letting their children grow up.
In the anime
Ash, ready to go on a new journey
The anime follows the Pokémon journey of Ash Ketchum, who started off with his first Pokémon, a Pikachu, in the first episode, and continues to journey across the world in order to compete in each of the regional Pokémon League competitions. His ultimate goal is to become a Pokémon Master. He is joined by his friends along the way, each with their own goals.
The anime has established that children may apply for their Pokémon Trainer's license, obtain their first Pokémon, and set out on their journey at the age of 10. Ash and many others received their starter Pokémon from the resident Professor, while some have received theirs from a local Pokémon Center or by other means. Seven-year-old Max, although barred from owning Pokémon, accompanied his sister May on her journey. Sometimes children younger than 10 have been shown to have Pokémon in their possession, notably Iris who had a Drilbur at a young age.
Starting a Pokémon journey is considered a rite of passage for children, and Ash has followed in the footsteps of both his father and grandfather. A journey can continue into adulthood, which is the case for Silver and apparently Ash's father. Adult Trainers, such as Cynthia, may eventually choose to remain in one place rather than traveling. Mandy even views an adult on a Pokémon journey as somewhat immature, preferring that they settle down instead.
Pokémon journeys have many different possibilities, with some Trainers choosing to gather a region's Badges from its Pokémon Gyms, their ultimate goal being the Pokémon League challenge. Other Trainers instead choose to become Coordinators, gathering Ribbons by competing in Pokémon Contests with the goal of winning the Grand Festival to become a Top Coordinator. Some other Trainers may choose to become Performers and compete in Pokémon Showcases with the goal of being the Kalos Queen. Others journey in order to learn about and be proficient about certain types of Pokémon while some may choose to journey to pursue certain occupations like Pokémon breeding, Pokémon watching, and Pokémon styling. Regardless of the reason behind the journey, Trainers must learn to work in all sorts of circumstances to become the best in their field.
In the manga
In the Pokémon Adventures manga
Pokémon Adventures follows the journeys of its protagonists in each of their self-named chapters: Red, Blue, and Green star in the Red, Green & Blue chapter, Yellow stars in the Yellow chapter, Gold, Silver, and Crystal star in the Gold, Silver & Crystal chapter, Ruby and Sapphire star in the Ruby & Sapphire chapter, and are joined by Emerald in the Emerald chapter with Gold and Crystal also join in later on, Red, Blue, Green, Yellow, and Silver return to the forefront in the FireRed & LeafGreen chapter, Diamond, Pearl, and Platinum star in the Diamond & Pearl chapter, later mainly going separate paths in the Platinum chapter, Gold, Silver, and Crystal star again in the HeartGold & SoulSilver chapter, and Black and White star in the Black & White chapter.
In other languages