The relationship between daydreaming and well-being were examined with mindfulness and consumption of Otaku contents (animations and games) as potential moderators. Recent theory suggests that both the context and contents of daydreaming matter in determining the beneficial effects of daydreaming. Mindfulness is a candidate for the former, whereas Otaku contents represent one for the latter. Metacognitive awareness and intentionality of daydreaming, and accepting relationship with the same, may facilitate such beneficial effects. As Otaku consumers obsessively engage in the imaginative contents, they will be adept at enjoying daydreaming of favorite contents. In Study 1, a survey of a large adult sample (n = 800), hierarchical regression analysis was employed to predict wellbeing from the three-way interaction of daydreaming × mindfulness × Otaku consumption. Significant three-way interactions emerged, predicting both life satisfaction and psychological well-being. Those high on either the non-judging facet of mindfulness or Otaku consumption showed a positive relationship between daydreaming and life satisfaction. Those low on both non-judging mindfulness and Otaku consumption showed a negative relationship between daydreaming and psychological well-being. In Study 2 (n = 104), priming of Otaku contents was employed in lieu of individual differences in Otaku consumption. Without Otaku priming, higher mindfulness revealed a positive relationship between daydreaming and life satisfaction. In addition, Otaku priming with short stimulus viewing time showed a positive relationship between daydreaming and subjective well-being (life satisfaction/positive mood). The results suggested that both contents and context of daydreaming affect well-being.