Who is the greek goddess of the ocean?

There is more than one Greek goddess of the ocean. The main ruler of the ocean is Poseidon, but he's a god, so let's leave him out for now.

Aphrodite - also the goddess of love - is known as as the goddess of the ocean. Alcyone and Amphitrite are the goddesses of the sea.

The one known as the Sea Goddess is Leucothea.

The sea nymphs are the Nereids and the Oceanides. There are 50 Nereids and 40 Oceanides.