This study examines the effect of relationship marketing (RM) tactics — financial, social, and structural — on customer satisfaction, and traces how satisfaction shapes relationship quality (a composite of trust and commitment) and, ultimately, customer loyalty at Abadan Port. The conceptual model was adapted from Caliskan and Esmer’s framework, and five hypotheses were formulated to test this sequential chain. The study is applied in purpose and descriptive-survey in method. The population comprised approximately 110 customers of Abadan Port, including cargo owners, shipping companies, transport companies, and customs brokers. Using the Krejcie–Morgan table and purposive sampling, 86 experienced respondents were selected. Data were collected via a 25-item, five-point Likert-scale questionnaire and analysed using partial least squares structural equation modelling (PLS-SEM) in SmartPLS with bootstrapping, following confirmation of non-normal data distribution. The measurement model showed satisfactory reliability and convergent and discriminant validity. Results showed that social (β = 0.315, p = 0.022) and structural (β = 0.471, p = 0.002) RM tactics had a positive, significant effect on customer satisfaction, while financial tactics did not (β = 0.093, p = 0.365). Customer satisfaction strongly predicted relationship quality (β = 0.894, p < 0.001), which in turn strongly predicted customer loyalty (β = 0.846, p < 0.001). The model explained 68.3%, 79.9%, and 71.6% of the variance in customer satisfaction, relationship quality, and customer loyalty, respectively. These findings underline the strategic importance of structural and social RM tactics as prerequisites for sustainable relationship quality and long-term loyalty in the port industry.