The development of fish product exports is of particular importance for the expansion of non-oil exports due to their higher value added, longer shelf life, and greater ability to penetrate international markets. This study aimed to evaluate the comparative advantage and examine the export specialization pattern of Iran’s fish products over the period 2002–2023. To assess export competitiveness, the Revealed Comparative Advantage (RCA) index and its symmetric form were employed. In addition, a convergence model based on the Revealed Symmetric Comparative Advantage (RSCA) index was used to investigate the dynamics of export specialization, while a sanctions intensity variable was incorporated into the model. The results showed that the RCA index was greater than one throughout the study period, indicating that Iran enjoyed a comparative advantage in exporting this product group. Moreover, the RSCA index remained positive and relatively high in most years, with an average of about 0.88, suggesting a relatively stable competitive position for these products in the global market. The results of the specialization model also revealed that the lagged RSCA coefficient was positive and statistically significant at the 5% level, whereas the coefficient of sanctions intensity was not statistically significant. Overall, Iran’s fish product exports exhibited a relatively stable comparative advantage, and sanctions were not able to structurally alter the export specialization pattern of these products.