This study examined the effectiveness of a multicomponent positive intervention self-administered through email to improve the personal well-being. Thirty-two university students participated in a 6-week positive intervention (IG) and thirty students were assigned to the control group (CG). The intervention consisted of positive activities such as savoring, gratitude, kindness, positive thinking and writing about the best possible selves. Both groups showed similar scores on well-being and personality characteristics at baseline, except in personal growth. The IG improved in positive affect, self-esteem, optimism and emotional clarity when pre- and post-treatment measures were compared. Positive affect increased in IG compared to CG. Responsibility and openness to experience explained the changes in subjective and psychological well-being after the intervention. Although the positive intervention had beneficial effects on some components of subjective well-being for the IG, some improvements were also observed in the CG that limit the scope of this intervention.