Sepia joubini is a species of cuttlefish native to the southwestern Indian Ocean, specifically South Africa, off Tugela River Mouth (29°11′S 31°25′E), to Cape Natal, off southern Mozambique (24ºS to 25ºS), and in the Saya-de-Malha Bank. It lives at a depth of between 66 and 170 m.Females of S. joubini grow to a mantle length of 64 mm.The type specimen was collected off Durban, South Africa. It is deposited at The Natural History Museum in London.