The rapid expansion of digital media has positioned online advertising as a critical instrument influencing tourists’ behavioral decisions. However, empirical evidence remains limited regarding which specific dimensions of online advertising quality most effectively shape destination perceptions and tourists’ behavioral intentions. This study aims to empirically examine the effects of online advertising quality dimensions—timeliness, personalization, localization, and perceived enjoyment—along with customer innovativeness, on tourists’ behavioral intentions, emphasizing the mediating role of perceived destination attractiveness. This applied research adopts a descriptive–survey design. The statistical population consists of tourists staying at five-star hotels in Mashhad, Iran. Data were collected using a standardized questionnaire and analyzed through Partial Least Squares Structural Equation Modeling (PLS-SEM) using SmartPLS software. The findings reveal that personalization, localization, and perceived enjoyment of online advertising have significant positive effects on perceived destination attractiveness, which, in turn, significantly mediates their relationships with tourists’ behavioral intentions. In contrast, the mediating role of perceived destination attractiveness in the relationships between advertising timeliness and customer innovativeness with behavioral intentions was not supported, indicating the predominance of direct effects for these variables. Moreover, perceived enjoyment emerged as the strongest predictor of tourists’ behavioral intentions. These findings highlight the strategic importance of designing experience-oriented, engaging, and audience-tailored digital advertising in the tourism sector. The study offers practical insights for tourism marketers and destination management organizations seeking to enhance the effectiveness of digital advertising strategies and influence tourists’ behavioral responses.