Varuna is the Hindu deity associated with water and the celestial ocean.
Varuna is one of the oldest and most important deities of the Vedic tradition, but his role changed over time. In the Rigveda, he is a sovereign of the sky and guardian of rita, the cosmic and moral order. He watches over truth, law, and the regular movement of the heavens, while also being linked with the primeval celestial waters.
In later Hindu mythology, Varuna’s identity becomes more specifically aquatic. He is described as lord of oceans, rivers, lakes, and streams, dwelling in an underwater palace. He is often shown riding a makara, a crocodile-like aquatic creature, and carrying a pasha, or noose. He also becomes a dikpala, the guardian of the western direction.
The description can therefore sound broader than a simple “water god”: Varuna began as a cosmic sovereign whose domain included sky, order, and sacred waters before becoming chiefly associated with the seas. Kubera governs wealth, Vayu the wind, and Agni fire, so none is the best answer here.