Ona is the No. 8 international prospect of the 2016 class, according to MLBPipeline.com. The righty slugger hit .319 for Cuba's 18U National League team in 2014 and starred at the 2014 COPABE 18U Pan American Championship in Mexico.
Earlier this month, the Padres inked Cuban pitcher Adrian Morejon to an $11 million deal.
Ona's deal is pending a physical.
Alex Putterman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.