The Cassiopeia Coin is one of the one hundred Constellation Coins that can be collected in Endless Ocean: Blue World. It can be found in the Deep Hole area of Gatama Atoll, on the sand at coordinates A-3 in the Coliseum area of the Hole (close to a separate zoom-mode glow). In this coin's zoom-mode patch, one or two Singular Bannerfish make their homes.
- The constellation upon this coin is meant to depict Cassiopeia, and Queen of Aethiopia. She was married to Cepheus, and was mother to Andromeda.
- As punishment for her boast that she and her daughter Andromeda were more beautiful than the sea nymphs, Andromeda was chained to a rock and left as prey for the sea monster Cetus by Poseidon. She was eventually rescued by the hero Perseus.