To support the global strategy to raise public health through walking among adults, we added the evidence on predictors of walking behavior in the Middle East and North Africa (MENA) region by emphasizing the mediator—COVID-19. During the COVID-19 outbreak, public restrictions to encompass the spread of the disease have disrupted normal daily lifestyles, including physical activity and sedentary behavior. It was proposed that tremendous changes have occurred on predictors of physical activity in general and walking behavior in particular for three types of walking, including commute, non-commute, and social walking compared to pre-COVID-19 time. This study aimed to identify the determinants of the walking types mentioned above, including subjective and objective variables before COVID-19, and compare them during the COVID-19 period in a sample from Iran, which has not yet been addressed in previous research. Adults (N = 603) finalized an online survey between June 5 and July 15, 2021. This group reported their individual/socioeconomic locations (e.g., home/work) and perception features before and during COVID-19. The paper developed six Binary Logistic (BL) regression models, with two models for each walking type (commute, non-commute, and social walking). For commute trips before COVID-19, the findings showed that factors including BMI, residential duration, p. (perceived) neighborhood type, p. distance to public transport stations and job/university places, p. sidewalks quality, p. facilities attractiveness, p. existence of shortcut routes, commute distance, building density and distance to public transport were correlated with commute walking. At the same time, such associations were not observed for BMI, p. distance to public transport and job/university places, p. facilities attractiveness, building density, and distance to public transport during COVID-19. The variables include age, possession of a driving license, number of family members, p. neighborhood type, p. distance to grocery, restaurant, parking, and mall, p. existence of sidewalks, land-use mix, and distance to public transport indicated correlations with non-commute before COVID-19. However, p. distance to groceries and malls and the p. existence of sidewalks did not correlate with non-commute walking during COVID-19. Ultimately for social walking, age and income variables, and the considerable proportions of subjective variables (e.g., p. distance to services/land-uses, security, etc.), health status and building density were correlated with social walking before COVID-19. Nevertheless, most of the mentioned variables did not explicitly correlate with social walking during COVID-19. As for the implication of our study, apparently, special actions will be needed by urban authorities to encourage adults to enhance their walkability levels by fully considering both objective and subjective indicators and walking types, which will result in healthier lifestyles.