With the growing reliance on digital platforms for health information, digital health literacy (DHL) plays a pivotal role in shaping preventive behaviors. This cross-sectional study surveyed 1,200 urban youths aged 18–25 in Kuala Lumpur, Jakarta, and Manila to assess DHL levels and their association with vaccination uptake, diet, and exercise habits. Results showed that participants with higher DHL scores were 2.4 times more likely to engage in preventive health behaviors. Socioeconomic status and educational attainment were significant predictors of DHL. Findings emphasize the need for integrating digital health literacy into public health education to promote informed health decisions in the digital age.