The aim of the study was to examine the controlling style in two contexts of social influence: the team (i.e., coach and teammates) and the family (i.e., father and mother), as well as the mediational role of motivation (autonomous, controlled, and amotivation) and its relationship with boredom and burnout in young swimmers. To this end, 267 swimmers (140 girls and 127 boys) between 12 and 18 years of age (M = 14.26; SD = 1.61) were assessed. The results showed that in the team context, coaches’ controlling style directly promoted controlled motivation and boredom in their swimmers, and indirectly influenced burnout through the mediating role of swimmers’ controlled motivation. Teammates’ controlling style was directly associated with controlled motivation, amotivation, and burnout, and indirectly associated with boredom and burnout through the mediating role of amotivation. Regarding the family context, the father’s controlling style showed direct associations with controlled motivation and burnout, and indirect associations with boredom through the mediating role of swimmers’ controlled motivation. Finally, the associations of the mother’s controlling style with all the variables studied were neutralized by the father’s controlling interpersonal style. This study emphasizes the differentiating role of significant others when displaying controlling styles, and it confirms that the controlling style has a significant relationship with maladaptive sport practice experiences.