南海狮（学名：Otaria flavescens）主要分布于智利、秘鲁、乌拉圭和阿根廷沿岸，是南海狮属唯一的种类。

雄性南海狮的头非常大，鬃毛浓密，使它们成为有耳海狮中最像狮子的一种。雄性的重量是雌性的两倍。雄性和雌性都有橙色的向上翘的鼻子。雄性的鬃毛比雌性浅，而雌性的头部和颈部的毛皮比雄性浅。幼崽出生时为黑色或深棕色，换毛后变成巧克力色。南海狮的个头和重量很大。成年雄性的长度为2.73米，重量可达350公斤。成年雌性长度为1.8到2米，重量约为150公斤。南海狮是五种海狮中最两性异形的海狮。

The South American sea lion (Otaria flavescens, formerly Otaria byronia), also called the southern sea lion and the Patagonian sea lion, is a sea lion found on the Chilean, Ecuador, Peruvian, Uruguayan, Argentine and Southern Brazilian coasts. It is the only member of the genus Otaria. Its scientific name was subject to controversy, with some taxonomists referring to it as Otaria flavescens and others referring to it as Otaria byronia. The former eventually won out, although that may still be overturned. Locally, it is known by several names, most commonly lobo marino (sea wolf) and león marino (sea lion).