Studying tuna's nutritional composition and potential health benefits is essential for understanding its impact on health, particularly concerning the fatty acid (FA) and protein content in its edible parts. Tuna has a huge number of edible parts and each of them may differ in nutritional profile. Most studies on Thunnus genus only assess the nutritional value of the muscle in general. This study assessed the specific proximal composition and fatty acid profile of different edible parts of a 13 kg male Thunnus alalunga (Bonnaterre, 1788) caught in June 2023 in the Cantabrian Sea. Samples of 10 different tuna edible parts were taken at the fish market from a certified trader and subsequently frozen at -18°C until analyzed. ANOVA and Boferroni’s test (p<0.05) were performed. The moisture (oven dry, 103±2°C), ash (muffle furnace, 550±50°C), protein (Kjeldahl method) and energy content (UE Regulation No. 1169/2011) were significantly higher in the liver (75.0%), top and low loin (1.8%), top loin (28.2%) and belly (206.7 kcal/100 g), respectively. A total of 28 FAs (GC-FID with a HP5 column) were quantified as a percentage of the total fat extracted with the Soxtec method. In general, the value of total polyunsaturated FAs (PUFAs) was higher than that of total monounsaturated FAs (MUFAs) and total saturated FAs (SFAs). The belly was the tuna edible part with the highest values of fat content (12.5%) and PUFAs, n-3PUFAs EPA+DHA (eicosapentaenoic+docosahexaenoic) and h:H ratio (hypocholesterolaemic/hypercholesterolaemic) FAs. The belly and the tail cut had the highest values of EPA+DHA/total fat and PUFAs/SFAs. The belly and low loin showed the highest n-3/n-6 FA ratio. Compared with other parts, the top loin had the highest thrombogenicity index values. We concluded that there is significant variability in nutritional profiles among the samples, with some exhibiting particularly richness in n-3PUFA EPA+DHA beneficial to human health in terms of their fatty acid profile.