This study presents an empirically validated serious game proposal to cope with the challenges of apathy and lack of security in freshmen studying accounting. A review of the literature on serious games in accounting education found a dearth of studies identifying the factors that promote their effectiveness. Therefore, this study first analyses the Accounting Marathon board game's effectiveness in reinforcing the learning of accounting principles in an introductory accounting course. Secondly, since the Accounting Marathon is based on experiential learning theory, self-efficacy and learning motivation are proposed as mediating variables in the relationship between experiential learning and self-perceived academic performance. The sample consisted of 119 students who participated in the intervention. In terms of results, students who played the Accounting Marathon significantly improved their actual academic performance. Also, self-efficacy and learning motivation were significant mediator variables between experiential learning and self-perceived academic performance.