On August 1, 1763, de los Reyes and twelve other missionaries departed for New Spain from Cádiz, accompanying a mission led by Domingo Elizondo.
[1]: 5 [2]: 21 They landed in Veracruz that November, and de los Reyes made a circuit of the missions of the area before arriving at the monastery of Santa Cruz in spring 1765.
[3] On August 17, 1780, the King appointed de los Reyes bishop of the newly created diocese of Sonora.
[1]: 65 After a long journey over land, de los Reyes arrived in his new see of Arizpe on September 22, 1783,[1]: 80 bearing a royal charter which declared the small town a city.
[1]: 67 After less than a month, de los Reyes petitioned for his see to be transferred to Álamos,[1]: 81 where he took up residence towards the end of the year.