Kabu Trader Shun is an adventure game centered on protagonist Shun Aiba, the son of a famous stock trader who bent bankrupt and disappeared five years earlier. With the help of his father's former trading partner, Toru Narasaki, and Toru's pupil, Hanako Kirikagura, Shun's goal is to become a successful trader like his father before him.

The player takes on the role of Shun, whose goal is to make a large sum of money by purchasing and selling various stocks around a city. The player can further the plot by travelling to various locations, investing in new companies by buying stocks, and interacting with various characters. Stock trading takes place on a graph representing one or more stocks incurring profit or loss over the course of several days. The player can affect the direction of the graph by buying or selling at the correct time.

The game's versus trade mode pits the player against rival stock traders in battles, where they must race to make the most amount of money over a period of time or reach a set profit mark. Both the player and opponent have a spirit meter that increases or decreases depending on how successfully one guide's their stock graph during a match. If a meter decreases too much, the player or opponent must recover before continuing to trade, potentially allowing the other to get ahead. Various special skills called Trading Arts can be learned and equipped to allow the player or their opponent to directly affect one another's spirit during battle.