When traveling the Central California coast, heading northward, keep an eye peeled for estuaries emptying streams and creeks into the sea. These tend to be the best spots for coastal jaspers to be on the beach--especially if the source formation is not off too far yonder in the distant mountains. Such is the case where the Santa Ynez River empties into the Pacific; do not expect to find rich jasper alluvium along the shore. To get to Santa Ynez jasper, you need to drive to the head waters of the river, namely where Upper Oso creek comes down from the rugged cliff formations before it joins the Santa Ynez River.
Unfortunately, there is an Estuary in the Goleta area that is inaccessible due to private landholdings. The best luck begins in San Luis Obispo County and continues northward up the coast. However, there are good jaspers to be found along "Surfer's Point," south of the mouth of the Ventura River, about an hour north of Los Angeles. Picking up quality jasper from a beach is truly the best way to hound jasper.