The Spanish colonisation of the Philippines relied on yearly dispatches of soldiers across the Pacific from New Spain. While professional Spanish soldiers formed the backbone of missions of conquest and exploration, they were in reality numerically weak. Royal officials in Manila struggled throughout the century to cover the bare necessities of defence let alone extend Spanish domination across the region. Faced with a chronic shortage of voluntary recruits, officials in New Spain and the Philippines increasingly relied upon a multiethnic mix of criminals and vagabonds found in the urban centres and rural highways of New Spain, who were impressed and coerced into military service. At the same time, however, conditions experienced in the Philippines equally undermined the effectiveness of the military. Widespread shortages in silver and supplies meant that soldiers existed in a state of chronic poverty and many chose to desert or turn to criminality. Thus, by examining the Spanish side of conquest we find that loyalty to the project of empire amongst those who were supposedly its chief protagonists was often contingent. By closely examining the social composition of Spanish soldiers serving in the Philippines in the seventeenth century, this article directly challenges the assumption that all Spanish agents of the colonial project in the Pacific were motivated by goals of self-aggrandisement and personal enrichment.