Substance use is characterized by reward processing dysregulation and cognitive control deficits. One area of research that remains relatively unexplored is the relationship between substance use and exploration-exploitation trade-offs, which involve a continuum from switching (exploration) to perseverative (exploitation). In dynamic, volatile environments, exploitation of well-known options can lead to habit-driven perseveration, and exploration of new opportunities can produce new information that may enhance one's future state. The primary aim was to investigate the relationship between regular substance use and spontaneous eyeblink rate (EBR) on exploration-exploitation behavior. Young adults (N = 83) aged 18-23 completed a single laboratory session. A dynamic foraging task was used to characterize exploration/exploitation behavior. Substance use was defined using the Externalizing Spectrum Inventory-Brief Form. Dopamine levels were operationalized using spontaneous EBR. The primary outcome was proportion of switch choices on the foraging task, which reflects a continuum of exploitation (low values) to exploration (high values) behavior. A linear mixed-effects regression was conducted to examine the effect of substance use and EBR on the proportion of switch trials. Results demonstrated a significant negative interaction between substance use and EBR on proportion of switch trials (p < .001). Participants with regular substance use and low EBR showed decreased switch choices, indicative of increased exploitation, compared to those with higher EBR. EBR was positively associated with proportion of switch trials (p = .032) and thus greater exploration. The relationship between substance use and increased exploitation in young adults appears specific to those with low EBR. (PsycInfo Database Record (c) 2022 APA, all rights reserved).