However, by the 1770s, rivals began to appear for the first time in the form of British and Russian fur traders, and King Charles III of Spain sent forth from Mexico a number of expeditions between 1774 and 1791, to reassert historic Spanish claims, and to explore the northern Pacific Coast of North America, including Alaska.
The second expedition, led by Lieutenant Bruno de Hezeta aboard the Santiago, along with 90 men set sail from San Blas on March 16, 1775 with orders to make clear Spanish claims for the entire northern Pacific Coast. Accompanying Hezeta was the escort and supply ship Nuestra Señora de Guadalupe (generally known as the Señora), initially under the command of Juan Manuel de Ayala. The 37 foot (11 m) schooner and its crew complement of 16 were to perform coastal reconnaissance and mapping, and could make landfall in places the larger Santiago was unable to approach on its previous voyage; in this way, the expedition could officially reassert Spanish claims to the lands north of Mexico it visited.
The two ships sailed together as far north as Point Grenville, Washington, named Punta de los Martires (or "Point of the Martyrs") by Hezeta in response to an attack by the local Quinault Indians. By design, the vessels parted company on the evening of July 29, 1775 with the Santiago continuing to what is today the border between Washington state and Canada. The Señora (now with second officer Juan Francisco de la Bodega y Quadra at the helm) moved up the coast according to its orders, ultimately reaching a position at Latitude 59° North on August 15, entering Sitka Sound near the present-day town of Sitka, Alaska. It is there that the Spaniards performed numerous "acts of sovereignty," naming and claiming Puerto de Bucareli (Bucareli Sound), Puerto de los Remedios, and Mount San Jacinto, renamed Mount Edgecumbe by British explorer James Cook three years later.
Throughout the voyage, the crews of both vessels endured many hardships, including food shortages and scurvy. On September 8, the ships rejoined and headed south for the return trip to San Blas.
In 1790, Spanish explorer Salvador Fidalgo led an expedition that included visits to the sites of today's Cordova, Alaska and Valdez, Alaska, where acts of sovereignty were performed. Fidalgo went as far as today's Kodiak Island, visiting the small Russian settlement there. Fidalgo then went to the Russian settlement at Alexandrovsk (today's English Bay or Nanwalek, Alaska), southwest of today's Anchorage on the Kenai Peninsula, where again, Fidalgo re-asserted the Spanish claim to the area by conducting a formal ceremony of sovereignty.
In 1791, the King of Spain gave Alejandro Malaspina command of an around-the-world scientific expedition, with orders to locate the Northwest Passage and search for gold, precious stones, and any American, British, or Russian settlements along the northwest coast. He surveyed the Alaska coast to the Prince William Sound. At Yakutat Bay, the expedition made contact with the Tlingit. Spanish scholars made a study of the tribe, recording information on social mores, language, economy, warfare methods, and burial practices. Artists with the expedition, Tomas de Suria and José Cardero, produced portraits of tribal members and scenes of Tlingit daily life. A glacier between Yakutat Bay and Icy Bay was subsequently named after Malaspina.
In the end, the North Pacific rivalry proved to be too difficult for Spain, which withdrew from the contest and transferred its claims in the region to the United States in the Adams-Onís Treaty of 1819. Today, Spain's Alaskan legacy endures as little more than a few place names, among these the Malaspina Glacier and the town of Valdez.