Felimare bilineata is a species of colourful sea slug or dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.

[2][3] This nudibranch is known from the Eastern Atlantic Ocean (from Portugal to Ghana) and the Western Mediterranean.

[4] Felimare bilineata has a blue body with an orange-lined mantle.

The upper dorsum and body have one or two orange longitudinal lines running down the length of the animal.

There are two lines at the base of the outer side of each gill, converging at the tip.