<p>This study evaluated the associations of commercial breeding-purpose category and seasonal period with CASA-derived sperm motility and kinematic variables in boars managed under commercial tropical conditions. We further explored whether the magnitude of seasonal variation differed among commercial breeding-purpose categories. Data were analysed using mixed models that separately evaluated seasonal effects (rainy, dry, transition), with boar included as a random effect, commercial breeding-purpose category (maternal, paternal, terminal), and their interactions. Season significantly affected sperm performance. The dry season was characterized by lower total motility and less favourable sperm kinematic profiles, whereas progressive motility was highest during the transition season (<i>p</i> &lt; 0.05). Commercial breeding-purpose category also influenced ejaculate quality; the terminal category showed higher total motility and fewer static sperm than the maternal category, whereas the paternal category exhibited a higher proportion of fast sperm (<i>p</i> &lt; 0.05). Several traits showed category × season interactions, revealing that some commercial breeding-purpose categories showed less pronounced seasonal variation. Season and commercial breeding-purpose category jointly influence semen suitability for artificial insemination and should be incorporated into boar management and selection strategies in tropical production systems.</p>