Francisco Coimbre was born in Coamo, Puerto Rico, to Guillermo Coimbre and Zoila Atiles. Upon his birth, he was inscribed as a resident of Arroyo in his birth certificate, following a common practice at the time. In 1922, he moved to Ponce along his mother, in order to live closer to his sister, Angela Coimbre. There he began playing baseball under the training and supervision of Miguel Caratini and Antonio Gordan, two hall of famers in the local league.
