After the discovery of America, Spanish migration to the Indies was a constant linked to the colonisation of the new territories which produced a steady flow of emigrants to the continent. However, the colonial age is not very relevant to migratory movements if we compare it with the emigration that took place during the 19th and 20th centuries.
In keeping with the dynamics of certain European countries, between the end of the 19th century and the first thirty years of the 20th century, Spain became a country of economic emigration. The period of greatest migration, which Nicolás Sánchez Albornoz coined as "mass emigration", mainly took place between 1880 and 1930. This is the age of massive emigration of Spaniards to America, which had a social importance and demographic weight way above that of the colonial era. During this chronological period, the American continent opened its doors to immigrants. Many governments believed that the solution to the lack of labour and the exploitation of new products lay in this group of people, and that their work force could materially develop emerging states
The study of migratory movements during this age shows that the emancipation of new Spanish-American republics did not result in the total rupture with the mother country but that during this period migration continued towards American possessions belonging to the Spanish crown until 1898, mainly to Cuba.
It is difficult to calculate the exact number of Spanish emigrants leaving to America during this period due to the dispersion of sources, but it fluctuates between two and four million people according to authors, the figure depending on whether or not an estimation has been made of how many returned. Some calculations place the rise in illegal or unrecorded immigration at almost 20%. Of all the Ibero-american countries receiving Spanish workers, Argentina and Cuba recorded the highest percentage of continuous flow, as immigration was encouraged by various governments and strengthened by family networks. The main shipping companies of the age dealing with passenger traffic included Compañía Transatlántica, La Bandera Española, Pinillos, Izquierdo y Cía., Messageries Maritimes, Pacífic Stearn Navigation Co., Compagnie Generale Trasatlantique, CunardLine, Hamburg Amerika Line, Compañía Naviera Sota y Aznar, and Navigazione Generale Italiana.
The Great Depression during the thirties put an end to massive emigration to America, although the phenomenon did not simply vanish. At this time, host countries started to restrict the entrance of new immigrants.
However, the Spanish Civil War saw the start of a new migratory wave: exile. Mexico, under the presidency of Lázaro Cárdenas, rescued and received between fifteen and twenty thousand exiled Spanish republicans from refugee camps in France, and became one of the main host countries.