Urban tourism in coastal cities such as Nowshahr faces challenges including heavy traffic, air pollution, and pressure on natural infrastructure. Cycling, as a clean and healthy mode of transport, can play a key role in achieving sustainable tourism. The present study aims to analyze the impact of cycling on the development of sustainable tourism in the city of Nowshahr. This research is applied in terms of purpose and survey-based in terms of method. The statistical population consists of the citizens of Nowshahr, and 384 individuals were selected as the sample. Data were collected using a questionnaire and analyzed through structural equation modeling (PLS-SEM). The findings indicate that the physical and social dimensions of cycling have a positive and significant effect on tourism development, both directly and through the mediating variable of "satisfaction with cycling." Satisfaction with cycling, with a path coefficient of 0.799 and an effect size of 2.876, plays the strongest role in explaining tourism development. The direct effect of the physical dimension on tourism development (0.150) is weaker than its indirect effect through satisfaction (0.379). The conclusion is that merely creating physical infrastructure without attention to the quality of experience, safety, and attractiveness of routes cannot lead to sustainable tourism development. Accordingly, enhancing user satisfaction with cycling routes, integrated planning, and combining physical infrastructure with social and perceptual components constitute an effective strategy for achieving sustainable tourism in the city of Nowshahr.