Mind wandering and daydreaming reflect non-deliberate and deliberate forms of mental exploration. However, it is not yet known to what extent the kinds of things that come to mind during these exploratory events are similar or different. The current research addresses this question by having participants engage in either a mindfulness task or a daydreaming task, with instructions to self-report novel thoughts as they occurred. Participants were then asked to rate their thoughts on valence, time orientation (past/present/future), and reality orientation (imaginary vs. real). Additionally, their emotional state was assessed using the Emotion Recall Task and PANAS questionnaire. Daydreaming produced a significantly greater number of thoughts compared to mind wandering. Daydreaming thoughts were also more positively valenced and future-oriented. Approximately 25% of thoughts were rated as imaginary, and this did not differ between mind wandering and daydreaming. However, an increase in future thinking was associated with a higher number of imaginary thoughts. Thought valence was predicted by both PANAS and ERT. These results suggest that mind wandering and daydreaming, while sharing many similarities, produce different kinds of thoughts and are not interchangeable.