Phacelia insularis, the coast phacelia is a rare species of phacelia. It is endemic to California, where it has a disjunct distribution.
Phacelia insularis is an annual herb with stems reaching about 20 centimeters long, the North Coast variety decumbent or somewhat upright and the island variety growing erect. It is glandular and coated in stiff hairs. The leaves may be up to 8 centimeters long and are borne on petioles. The larger leaves have blades divided deeply into lobes. The inflorescence is a one-sided curving or coiling cyme of many purple flowers. The North Coast variety has bell-shaped flowers under a centimeter in length, while the island variety has wider, sometimes larger flowers.