The first purpose of this study was to investigate what motivated spectators to attend games of the Hiroshima Toyo Carp (Carp). The second purpose was to investigate the influence of previous attendance at Carp games in 2012 and seat types on the motivation for attending games. Among the spectators of baseball games that took place on September 18 and 19, 2012 at the Mazda Zoom-Zoom Stadium Hiroshima (Mazda Stadium), 467 completed a questionnaire. The questionnaire included items related to demographic information, the number of times the spectators had watched games at Mazda Stadium that year, the type of seat they occupied on the day, the team they supported that day, their favorite team, and 17 motivation items from a modified version of the Sport Spectator Motivation Scale. The results showed that the spectators were strongly motivated by “pleasure of spectating games,” “devotion to the Carp,” and “exciting play.” Motivation scores for “devotion to the Carp,” “attachment to Hiroshima,” and “cheering” increased as the number of previous attendance increased. The scores for “being invited by friends or family members” and “spending time with friends or their boyfriend or girlfriend” were higher for spectators occupying group seats than those in individual seats. These results suggest that increasing the number of spectators at Mazda Stadium games demands multiple strategies to match spectators’ needs.