The first Old Worlder to contact the Nicoleño was the Portuguese explorer Juan Rodríguez Cabrillo, sailing for Spain. He landed on San Nicolas in December 6, 1603 and reported that the island was densely populated. Little is known of the Nicoleño through the historical record between that date and the early 19th century, but the population seems to have declined significantly, likely due in part to Spanish missionary recruitment efforts, known to have relocated people from the other Channel Islands to the mainland.
In 1811 a party of Aleuts from Russian Alaska landed on San Nicolas in search of sea otter and seal. They fought with the Nicoleño men, probably over hunting rights and women, and many died as a result. The tribe was decimated, and by the 1830s only around twenty remained; some sources put the number at seven, six women and a man named Black Hawk. Hearing of this, the Santa Barbara Mission on the mainland sponsored a rescue mission, and in late 1835 Captain Charles Hubbard sailed out to the Channel Islands aboard the schooner Peor es Nada. Most of the tribe boarded the ship, but one, the woman later known as Juana Maria, did not arrive before a storm rose and the ship had to return to port. Hubbard was unable to return for Juana Maria at the time as he had received orders to take a shipment of lumber to Monterey, California, and before he could return to Santa Barbara the Peor es Nada hit a heavy board in the mouth of the San Francisco Bay and sank. A lack of other available ships is usually cited as preventing further rescue attempts.
Many of the surviving Nicoleño chose to live at the Mission San Gabriel Arcángel, however, they had no immunity to the diseases they encountered there. Black Hawk became blind shortly after arriving, and died when he fell off a steep bank into the water and drowned. The others had also apparently died by the time Juana Maria was rescued. After several other attempts at locating her failed, she was found by Captain George Nidever, who took her to the mainland. None of the local Indians could decipher her language, and she was taken in by Nidever and his wife. However, she contracted dysentery and died only seven weeks after her return to civilization.
The first archaeological visit to San Nicolas was by Paul Schumacher for the Smithsonian Institution in 1875. They uncovered numerous artifacts from surface sites, assumed to be from a later period of Nicoleño culture, as the island's climate is not well suited for preservation. Artifacts collected by these early visitors include grass matting and clothing fragments, bone knives and fishhooks, and soapstone fish and bird effigies. Nicoleño culture was entirely dependent on the ocean for sustenance, as the island was home to only four types of land animals, none of which were valuable for food. The island is home to a large abundance of fish and sea mammals, as well as birds, which the Nicoleño were skilled at catching.