These deities or gods had powers to control the elements of water and presided over all the fresh and salt water of the earth. They are associated with seas, sea-storms, waves, currents, sea-creatures, lakes, springs, rivers, fountains, marshes and ground waters.
Aegaeon - god of violent sea storms. He is referred as a son of Briareus, one of the three Hekatoncheires. During Titanomachy, Aegaeon was an ally of the Titans.
Achelous - god of the river Achelous who was the greatest and the oldest river of Ancient Greece. He was a son of Oceanus and Tethys and was represented as a god of fresh water in general.
Amphitrite - wife of Poseidon and a Queen of the seas. She was a personification of the sea itself and was a mother of dolphins, seals and fish. Amphitrite was thought to be a daughter of Nereus and Doris which would put her among the Nereids.
Benthesikyme - goddess of waves who presided over the sea of Ethiopia. She was a daughter of Poseidon and Amphitrite or a wife of King Enalos of Ethiopia.
Brizo - patron goddess of sailors and fishermen. She was also a prophet who specialized in interpreting dreams.
Ceto - goddess of the dangers of the sea. She was a daughter of Gaea and Pontus. Ceto was also more specifically identified as a goddess of sharks, whales and sea monsters.
Cymopoleia - goddess of violent sea currents and waves during storms. She was a daughter of Poseidon and was married to Briareus, one of the Hekatoncheires.
Delphin - leader of the dolphins who served Poseidon in his search and persuasion of Amphitrite. For his services he was placed among stars, known as the constellation Delphin.
Eidothea - prophetic sea nymph who instructed Menelaus to capture his father Proteus, if he ever wished to escape from the island Pharos where he was trapped.
Glaucus - prophetic sea-god who protected sailors and fishermen in difficult times during storms. He was once a mortal but was transformed into a sea-god after eating a magical herb.
Hydrus - primeval god of waters who had, according to some sources, emerged from Chaos alongside Gaea.
Leucothea - sea goddess who aided sailors in distress. She was once a mortal princess called Ino and was a daughter of Cadmus. Ino was punished by Hera for looking after infant Dionysus. The goddess made her to leap into the sea from a cliff. She was then, by the Olympian gods, renamed into Leucothea and transformed into a sea goddess.
Naiads - fresh water nymphs who presided over fresh water supplies of the earth, such as springs, rivers, lakes, fountains and marshes. They were classified into five groups, known as Pegaeae(springs), Potameides(rivers), Limnades(lakes), Crinaeae(fountains), and Eleionomae(marshes)
Nereides sea nymphs who presided over the Mediterranean Sea. They were particularly associated with Aegean Sea where they had dwelled in the depths, inside the silver cave. Most notable were Thetis (the leader of the Nereids), Amphitrite (the one who left the Nereids to become a wife of Poseidon and a Queen of the seas), and Arethusa (she transformed herself into a stream on the island of Ortygia in order to escape embraces of river god Alpheus).
Nereus - the Old Man of the Sea who had the power of prophecy and shapeshifting. He was the eldest son of Pontus and Gaea, born in titans generation. Nereus was a father of Nereids by Doris.
Nerites - young sea god whom Aphrodite fell in love with. Upon rejecting the goddess to join her at Olympus, Aphrodite turned him into a shell-fish.
Oceanides - three thousand fresh water nymphs, daughters of Oceanus and Tethys. They presided over all the fresh water on earth and were separated into three groups, known as Naiads (spring, fountain, river, lake nymphs), Aurai (breeze nymphs) and Nephelai (cloud and rain nymphs), where the last two became associated with Sky deities.
Palaemon - young sea-god, the protector of sailors in danger. His mortal name was Melicertes whose parents enraged Hera by taking care of young Dionysus. His mother Ino leapt into death with him. He, along his mother, was transformed into a sea-god by the Olympians and was renamed into Palaemon, while his mother Ino became Leucothea.
Phorcys - primeval sea-god of hidden dangers of the deep. He was a son of Pontus and Gaea and was married to Ceto, with whom he was a father of sea monster Scylla, draconian Ladon and the three Gorgons.
Pontus - primeval god of the sea. He was one of the first-born gods and was a father of most of the ancient sea gods by Gaea. With his consort Thalassa they presided over the seas, fish and other sea creatures.
Potamoi- three thousand river gods, born to Oceanus and Tethys. They were brothers of Oceanids and husbands of Naiads. Most known were Achelous (river Achelous in central Greece) Acis (river of Sicily) Acheron (river of Pain), Asopus (river of Boeotia), Cocytus (river of Wailing), Lethe (river of Oblivion), Phlegethon (river of Fire), Styx (river of Hatred) and Scamander (river of Troy in Anatolia).
Proteus - ancient sea-god with the power of prophecy and shape-shifting. He was a herdsman of Poseidon's seals and was associated with the island of Lemnos.
Sirens - sea nymphs who drew sailors to their death with their enchanting songs. Originally they were attendants and maids of Persephone, but when Hades had abducted her, Demeter gave them the bodies of birds in order for them to help with the search. The Sirens were encountered by Odysseus on his journey back to Ithaca and previously by Jason and the Argonauts.
Telchines - mysterious sea-magician spirits, related to the island of Rhodes. They were four brothers, descendants of Pontus and Gaea. It is said that they had crafted the sickle which Cronus castrated his father Uranus with. In the end, they were casted to Tartarus by Zeus who was angered by their malevolent use of magic.
Thalassa - primeval spirit of the sea. She was a consort of Pontus and together they presided over the seas.
Thaumas - god of the wonders of the sea. He was a descendant of Pontus and Gaea and was married with an Oceanid called Electra, with whom he fathered Iris (goddess of rainbow), Arce and Harpies.
Thoosa - goddess of swiftness who was associated with swift currents of the sea. She was loved by Poseidon and gave birth to Polyphemus, the famous one-eyed cyclops.
Triteia - fresh water nymph of the local spring of the town Triteia. She was a daughter of Triton and was a companion of Ares and later gave birth to Melanippus.
Triton - god and messenger of the sea. He was a son of Poseidon and Amphitrite. He is depicted and represented as a merman, with an upper body of a man and tail of a fish. According to Hesiod, he dwelt in a golden palace in the depths of the sea beneath Aegean Sea.