Father Janssen advised Father Eustace's parents to send him to the Latin School of Germet, where he remained for a year and a half.

At school, Eustáquio found a small book about the life of Father Damien of Molokai and felt inspired by it to live a missionary life dedicated to those most in need.

In testimony before the Tribunal for the Cause of Beatification and Canonization of Father Eustáquio, in 1962, Father Gil recounted:

“Regarding the period before his entry into the Seminary, I can only say that the boy, following his environment steeped in religiosity, practiced acts of piety, such as pilgrimages to sanctuaries, where the rosary was prayed aloud; this cannot be said to have been characteristic because it was common among that population. I can testify to these facts, as I know well the region from which Father Eustáquio came, and which is also my region..” (Father Gil)

In September 1905, Eustáquio enrolled in the Minor Seminary of the Sacred Hearts, Padre Damião Institute, in Grave, and in 1913 he completed his secondary education at the institution.