In 1914 the Pacific Coast Railway Company constructed a pier at Port San Luis for commercial shipping. The pier is located between the existing Avila and Port San Luis (Harford) Piers.
Union Oil Company of California (later Unocal) leased the new pier and expanded their operations. Oil was shipped from both the Port San Luis and the Pacific Coast Railway Co. Piers and Port San Luis become the largest crude oil shipping port in the world during this time. The current pier extends six-tenths of a mile into the bay and is constructed in the same footprint as the original pier.