Albacore typically reach sexual maturity at a length of 90 cm. The maximum recorded size is 140 cm and 60.3 kg. Weight varies considerably within the species, with immature albacore weighing less than 14 kg and mature albacore weighing more than 14 kg. One of the most distinguishable traits of albacore are the extremely long pectoral fins. In individuals longer than 50 cm, the pectoral fin can be 30% of the fork length. Because the closely related bigeye tuna (Thunnus obesus) also have extremely long pectoral fins, albacore are often confused with juvenile bigeye tuna. Pectoral fins of bigeye tuna have rounded tips while pectoral fins of albacore have more pointed tips. Because bigeye tuna grow much larger than albacore, only juvenile bigeye tuna are misidentified as albacore. In addition to long pectoral fins, albacore have very small scales covering their body, 11 to 14 dorsal spines, 12 to 16 dorsal soft rays, 11 to 16 anal soft rays, and no anal spines. Because the anterior spines are longer than the posterior spines in the dorsal fin, the dorsal fin appears to have a concave outline pointing back toward the tail. Albacore have a faint blue iridescent band along the side of the body as well as yellow shades in the dorsal and anal fins. Males are similar to females in appearance and color, but begin to grow larger in size after sexual maturity due to different growth rates.

Range mass: 60.3 (high) kg.

Range length: 140 (high) cm.

Other Physical Features: ectothermic ; bilateral symmetry

Sexual Dimorphism: male larger