San Luis Head, or Whaler Rock, in this bay, is midway between the light at Point Conception and that at Piedras Blancas, a distance of 94 unlighted miles. A light at this point will be a primary coast light, and will have the additional value of being a guide to Port Harford. The bay of San Luis Obispo is the most important roadstead on the Pacific coast south of San Francisco, and with one exception is also the best. The harbor is always good for eight or nine months in the year, and during the remaining time it is never actually bad. Its security is exceptional for an open roadstead. The commerce of Port Harford is now considerable and it is increasing yearly. It is the terminus of a railway which is the natural outlet for the agricultural products of that section, and many schooners loaded with timber make this port. In addition, the steamers of the Pacific Coast Steamship Company all touch here, averaging one steamer a day the year around, carrying both passengers and freight, and all of the steamers go to the wharf at the head of the bay. This company maintains a private light here, on which all the sailing vessels entering this port depend, none of which belong to the company. As the bay is subject to dense fogs for the greater part of the year, this company is now contemplating the establishment and maintenance of a steam fog signal here at their own cost. The Light-House Establishment acquired by executive reservation a small island about 500 feet from San Luis Head, called Whaler Island. It has obtained the refusal of 30 acres at the head, which it can purchase, together with adequate water privileges, for a reasonable sum. The necessity for a light and fog signal at this point has been pressed upon the attention of Congress from time to time and recently with increased vigor. At the last session of Congress a bill was passed by the House of Representatives for the appropriation of $20,000 to establish and maintain a fog signal at this point, but it failed to pass the Senate. As it now appears that a light is as much needed as a fog-signal, and that both are quite necessary to the commerce of this section, the Board recommends that an appropriation of $50,000 be made for the establishment of a light and fog-signal at or near San Luis Head, with authority, if need be, to place the one on the head and the other on the adjacent island.
Congress provided the requested $50,000 in 1886 for a fourth-order light and fog signal, and the inspector and engineer of the twelfth lighthouse district decided that both the light and fog signal should be placed on the mainland at San Luis Head.
The project suffered some initial setbacks. Acquiring a deed to the desired parcel on the headland at Point San Luis proved difficult, and then the first bids on the project were too high. While construction on the lighthouse was delayed, the need for a light at the harbor was punctuated by an event on May 1, 1888. The steamship Queen of the Pacific began taking on water fifteen miles out from Part Harford. The captain headed for the port, but with no light to mark the harbor, he was forced to make his way slowly in the dark. The water-laden steamship finally settled to the bottom of the harbor just 500 feet short of the pier. Fortunately, a good portion of the ship remained above the waterline, and the passengers were safely off-loaded.
Notice is hereby given that on or about June 30, 1890, a light of the fourth order, showing red and white flashes alternately, with intervals of thirty seconds between flashes, will be exhibited from the structure recently erected at San Luis Obispo. The focal plane is 133 feet above mean low water, and the light may be seen, in clear weather, from the deck of a vessel fifteen feet above the sea, seventeen and a half nautical miles. The light is shown from a black lantern surmounting a square frame tower attached to the southwest corner of a one-and-a-half-story frame dwelling painted white, trimmings lead color, blinds green, roof brown. About fifty yards to the eastward stands a one-and-a-half-story double dwelling painted in a similar manner, Between the two dwellings, and about fifty yards to the southward, stands the fog signal building with its two black smokestacks, and painted like the dwellings.
Three lighthouses were built in California using these plans, but Point San Luis Lighthouse is the only one that remains fully intact. As for its two sister lights, the tower of Table Bluff Lighthouse is all that is left, while Ballast Point Lighthouse was completely razed to make room for the expansion of the Naval submarine base in San Diego.
A cement watershed that collected rainwater and fed it into underground cisterns was built as part of the original work, but as the rainy season had already past, there was initially no water to operate the new fog signal. Rather than delay its activation, a pipeline was laid to Pecho Creek, a distance of three-and-a-half miles, and the fog signal commenced operation on August 10, 1890, sounding a five-second blast every forty seconds as needed. The signal was in operation roughly 1,000 hours each year, but for the twelve-month period ending June 30, 1895, it sounded 1,785 hours (over seventy-four days) and consumed ninety-six tons of coal.
From the eastern end of Point San Luis, a federal breakwater, which encompassed Whalers Island, was built between 1893 and 1913. A small wharf located near the juncture of the breakwater and the mainland provided the primary means of access to the lighthouse, though a crude wagon road also reached the station.
A first-class air siren, which was operated by gas engines and air compressors and had been used previously at Point Reyes, replaced the stations twenty-five-year-old steam whistle in 1915. The station was electrified in 1935, and the fog signal was changed at that time to a type F diaphone. During World War II, a radio listening station was built near the lighthouse, necessitating the erection of a second duplex.
Once the men had regained some strength, they recounted what had happened to their ship, the 267-foot-long S.S. Roanoke. Loaded with a cargo of 600 tons of dynamite, 1,300 tons of wheat, and several hundred drums of oil, the Roanoke had left San Francisco at midnight on May 8, bound for Valparaiso, Chile. While battling heavy seas off Point San Luis, the cargo in the steamship shifted, causing the Roanoke to flounder. Six lifeboats were launched by the crew that numbered forty-six, but only the three men aboard the lifeboat spotted by Keeper Smith and another man aboard another lifeboat survived the tragedy.
In 1961, the Coast Guard replaced the original double-dwelling with a one-story duplex. The Fresnel lens was deactivated in 1969 and replaced by a modern beacon. The station remained staffed for five more years until the station was fully automated in 1974.
Ownership of the thirty-acre light station was transferred to the Port San Luis Harbor District in 1992, and a non-profit group, the Point San Luis Lighthouse Keepers, was formed in 1995 to work towards the restoration of the light station. Besides the lighthouse, the fog signal building, oil house, two cisterns, two duplexes, and a privy remain.
Much progress has been made by the modern-day keepers. The exteriors of all of the structures were painted during the summer of 2003, and by that time, the parlor inside the lighthouse had been fully restored and furnished with period pieces provided by a local chapter of the Questers. After more than 65,000 hours of work by the volunteer keepers, the lighthouse, and fog signal building have since been fully restored.
In early 2010, the year San Luis Obispo Lighthouse celebrated its 120th anniversary, the Fresnel lens was returned to the station and placed on display in the horn house, which has been converted into a visitor center. The lens was removed from the lighthouse in the late 1970s after it was shot with a .22 caliber bullet and had been on display at the San Luis Obispo County Historical Museum and the San Luis Obispo Library, where it was housed in a modern lantern room. Also in 2010, the Point San Luis Lighthouse Keepers purchased a trolley and began offering trips to the lighthouse on the one-lane road that was rebuilt at a cost of $1.3 million.
In early 2012, renovation of the Coast Guard duplex next to the lighthouse was completed, and the Point San Luis Lighthouse Keepers relocated their office from downtown San Luis Obispo to the lighthouse grounds. Besides housing the office, the duplex can accommodate gatherings of up to eighty or one hundred people, allowing weddings and other functions to be held at the lighthouse.