Fish products are highly traded and global fish trade has been increasing very rapidly in recent decades with an estimated 45% of the world catch now traded internationally. West Africa has a huge potential for trade in intra-regional terms and vibrant markets for fish and fish products in Nigeria, Ghana and the Ivory Coast being the three major importers of fish products in the region. Intra-regional fish trade is important in improving food and nutritional security; and poverty eradication in Africa. However, trade has so far not served as an effective tool for the achievement of rapid and sustainable economic growth and development for many of the countries of the continent because, there is paucity of information on market structure and value of intra-regional fish trade. This information is needed to ensure the proper integration of intraregional fish trade into the nation-state policy agenda. This study therefore investigated the marketing structure, profitability and trade flow along the borders of Nigeria. In this study, Nigeria was divided into four major areas according to the countries at her borders viz: Nigeria-Cameroon-Chad, Nigeria-Niger, and Nigeria-Benin border and the Lake Kainjiinland fisheries with multi-stage experimental design adopted. Sixteen States including Akwa Ibom, Cross River, Benue, Taraba, Adamawa, Borno, Sokoto, Katsina, Jigawa, Yobe, Kebbi, Kwara, Oyo, Ogun, Lagos and Niger States along the borders were sampled. One hundred and eight (108) Local Governments Areas in the States were sampled based on the prevalence of fishing activities in these areas. Structured questionnaires were administered to a total of 814 producers, 814 processors and 814 marketers randomly selected based on their active involvement in fish marketing. Information on socio-economic characteristics, quantity and values of fish products marketed, trade flow and market structure were collected. Data collected were subjected to descriptive statistics, budgetary analysis, Gini coefficient, linear regression and ANOVA at α0.05. The results showed that fish production was dominated by males along the three borders with the highest percentage recorded in Sokoto and Katsina (100.0%), while more females were involved in processing and marketing in four States (Cross River, Akwa Ibom, Taraba and Benue States) along the Nigeria-Cameroon-Chad border with the highest percentage in Cross River (90.0% and 90.0%). About 1.69% of the fishermen along Nigeria-Cameroon border import fresh while 0.67% of the fish marketers import smoked and dried fish into Nigerian fish market. Marketers and processors of 1.51% were involved in cross-border importation of smoked fish into Nigeria through Nigeria-Benin border while 0.81% of the sampled marketers engaged in importation of fresh and dried fish products. 0.40% of the marketers and processors along Nigeria-Niger border and Lake Kainji-inland fisheries were involved in cross-border trade of dried and fried fish products. About 1.19% of the fish marketers export fried fish from Nigeria to Niger Republic through Nigeria-Niger border. Exportation of smoked fish of about 2008.22±856.51kg (₦3,260,028.25±1,231,860.25) was recorded in Jigawa State while dried fish of 1,800.00±0.00kg (₦4,606,200±0.00) and 2,500.00±0.00kg (₦4,425,000.00±0.00) were observed among respondents in Yobe and Niger States, respectively along Nigeria-Niger border and Lake Kainjiinland fisheries. Along Nigeria-Cameroon-Chad border smoked fish of 1,278.06±0.00kg (N2,581,672.22±0.00) and 951.56±214.34kg (₦2,136,666.84±306,413.18) were exported from Benue and Borno State, respectively. In Lagos State, 20.56% (1,088.75±292.76kg) and 31.69% (441.00±241.83kg) of the total smoked and dried fish, respectively traded in the State were supplied through the cross-border trade while 14.67% (2,300.00±424.26kg) and 4.50% (150.88±97.21kg) of fresh and smoked fish, respectively were imported from Benin Republic through cross-border trade in Ogun State. The Gini coefficient value for most of the actors in the States along the Nigeria-Niger border and Lake Kainji-inland fisheries was 0.34, 0.45, 0.41, and 0.43 for wholesalers of smoked fish, retailers of spiced fish, wholesalers and retailers of frozen fish respectively. The linear regression (b) coefficient for all the forms of fish were positive except for dried and fried whose b values were -7.66 and -5.15 respectively. Gini coefficients were 0.63, 0.70, 0.71 and 0.59 for fresh, smoked, dried and frozen fish markets in the States along the Nigeria-Cameroon-Chad border and the linear regression coefficient was positive for all forms of fish. The linear regression coefficient for all forms of fish marketed along the Nigeria-Benin border were positive except for fried fish with b value of -485.89. In conclusion, the fish markets along Nigeria-Niger border, Lake Kainji-inland fisheries, the Northern part of the Nigeria-Cameroon-Chad and the Nigeria-Benin border which includes Kebbi, Borno, Adamawa and Taraba States were dominated by males, while there were more females involved mainly in fish marketing and processing in the Southern part (Cross River, Akwa Ibom, Lagos and Ogun States) of these borders. Most respondents involved in fish marketing along the borders of Nigeria were married and in their economic active age with household sizes varying from medium to large. The fish markets in Nigeria-Niger border region and Lake Kainji-inland fisheries showed partial inequality in the revenue distribution of fresh smoked dried fried spiced and frozen fish; except for wholesalers of smoked, retailers of spiced, wholesalers and retailers of frozen fish. In addition, there was barrier to entry into fried and dried fish markets. Along Nigeria-Cameroon-Chad border, the fish markets exhibited partial equality in fresh, smoked, dried and frozen fish markets; except producers in fresh, processors in smoked and dried and wholesalers in dried fish markets. Evident from this study, informal cross-border trade (ICBT) of fish products were recorded across Nigeria-Cameroon-Chad, Nigeria-Benin and Nigeria-Niger Borders. The percentage of the respondents involved in ICBT were extremely low when compared to the percentage that engaged in inter-state and intra-state trade of fish products in the study areas. This is an indication that inter-regional fish trade between actors involved in fish marketing (value-chain) in Nigeria with the neighbouring countries is not a popular practice. Therefore, there is need to enhance inter-regional trade in Nigeria in order to enhance fish production in addressing food insecurity and poverty in the entire region. Dried fish was recorded as the most traded fish product across the regional borders. Therefore, structures should be put in place to enhance intraregional trade in Nigeria.