What level does Ekans evolve?

Ekans evolves into Arbok starting at level 22.

Ekans is #23 in the National Pokedex, and was introduced in the Generation I Pokemon titles (Red, Blue, and Yellow) where it could be found (Red only) on Routes 4, 11, and 23. In Generation VI (X and Y), it can be caught on Route 14 in a Horde encounter.