This study examined the effect of international seaborne trade on productivity of port in Nigeria. The predictor variable (international seaborne trade) had its dimensions as oil export, non-oil export, oil import and non-oil import. The criterion variable (productivity of port) was measured with port productivity. The theories that underpinned the study included: Comparative advantage theory and theory of international trade, ex-post facto research design was used for the study.Secondary sources of data were used as the main data collection method. Relevant data for this study were collected from the annual reports and accounts of Nigerian Ports Authority, National Bureau of Statistics and Central Bank of Nigeria Annual Statistical Bulletins (1981 -2022). The population of the study consisted of all the 6 ports in Nigeria. The study used descriptive and inferential statistical tools to analyse the data. Specifically, multiple regression analiysis of ordinary least square estimation was used to test the hypotheses with the aid of SPSS 26.0. The reliability of the research instrument was validated on the basis of the secondary data sources. The study revealed that there are opportunities to develop and use oil and non-oil export channels for international seaborne trade through ports. The study revealed that ports provide avenues for the use of oil and non-oil imports to smoothen international seaborne trade that leads to effective seaport performance. The study found that non-oil export and non-oil imports offer veritable opportunities to optimize international seaborne trade efficiency in ports by helping to convert resources, build traffic intensity in trade and engage customers and stakeholders to utilize ports for their international business transactions. The study revealed that ports recognize that oil export, non-oil export, oil import and non-oil import provide the government and business community variety of options to engage in seaborne trade of intensive nature. The study concluded that: Oil export has insignificant effect on productivity of ports in Nigeria (t = 1.592). Nonoil export has negative and insignificant effect on productivity of ports in Nigeria (t = -1.040); oil import has insignificant effect on productivity (= 0.948); non-oil import has insignificant effect on productivity (t = 0.775). This study, therefore, recommended that Nigerian ports should prioritize and utilize the full capacity available in seaborne trade and channel oil exports and non-oil exports towards increasing and optimizing the productivity of ports in Nigeria.