Several installments of Final Fantasy franchise gave the player the chance to take part in Chocobo races. Final Fantasy XV is one of those games as well. There are 7 different races available in the game. The first one, "Against Prompto", unlocks after completing "A Behemoth Undertaking" side quest and completing that race unlocks another one. Each subsequent race is unlocked once you finish the one preceding it. Races can be started by talking with an NPC located to the south of Wiz Chocobo Post.
The races in the game are divided into two groups - normal ones, in which you race against other members of the part, and Hoops, during which you will race against the time. The beginning races are quite simple, but the more advanced ones will test both the skills of the player, as well as the Chocobo itself. In order to finish some of the most difficult ones you might be forced to level up the Chocobo you are using all the way to level 10.
Below you can find a table containing information about all of the races available in the game, the requirements that must be met to unlock them and the rewards you will receive for winning them.
Complete "A Behemoth Undertaking" side quest.
Defeat Prompto in "vs. Prompto" race
Chocobo Hoops: Grande Gallop
Defeat Gladio in "vs. Gladiolus" race
Short Course Medal
Reach chapter 5 and complete Chocobo Hoops: Grande Gallop.
Defeat Ignis in "vs. Ignis" race
Fat Chocobo Medal
Chocobo Hoops: Rocky Road
Complete the Full Field race.
Long Course Medal
Reach chapter 6 and complete Chocobo Hoops: Rocky Road.
Note - you can get an additional reward called Jockey Master Medal. You have to complete all 7 Chocobo races and speak with the NPC at the booth (the same character you speak with to start a race).