Objective: This study was conducted to determine the level of health literacy, digital healthy diet literacy, and physical activity of adult individuals to evaluate the relationship of physical activity with health literacy and digital healthy diet literacy and to examine the determinants of physical activity level. Design and Method: It is a descriptive and correlational study. The sample of the study consists of 404 individuals aged 18–65. Personal Information Form, International Physical Activity Questionnaire—Short Form, Health Literacy Scale—Short Form, and Digital Healthy Diet Literacy Scale were used to collect the study data. Number, percentage, mean and standard deviation, t test in independent groups, one-way analysis of variance, and multiple regression analysis were used in the analysis of the study data. Results: Participants' gender (β = 0.572, p = 0.000), educational status (β = 0.630, p = 0.000), employment status (β = 0.573, p = 0.000), perceived economic situation (β = 0.774, p = 0.000), cohabitants (β = 0.609, p = 0.000), perceived health (β = 0.580, p = 0.000), smoking status (β = 0.639, p = 0.045), health literacy total score (β = 0.603, p = 0.000), and digital health literacy (β = 0.782, p = 0.000) were found to be predictors of physical activity level (p < 0.001). It was determined that these determinants explained 57.3% (adjusted R2 = 0.573) of the change in physical activity level. Conclusion: The mean scores of the participants' physical activity level were at a medium level. Increasing the participants' awareness of health literacy and digital healthy diet literacy may be effective in increasing the level of physical activity.