Both.
From the Catechism, on Predestination:
600 To God, all moments of time are present in their immediacy. When therefore he establishes his eternal plan of “predestination”, he includes in it each person’s free response to his grace: "In this city, in fact, both Herod and Pontius Pilate, with the Gentiles and the peoples of Israel, gathered together against your holy servant Jesus, whom you anointed, to do whatever your hand and your plan had predestined to take place."395 For the sake of accomplishing his plan of salvation, God permitted the acts that flowed from their blindness.396
From the Catechism, on Free Will:
1731 Freedom is the power, rooted in reason and will, to act or not to act, to do this or that, and so to perform deliberate actions on one’s own responsibility. By free will one shapes one’s own life. Human freedom is a force for growth and maturity in truth and goodness; it attains its perfection when directed toward God, our beatitude.
1732 As long as freedom has not bound itself definitively to its ultimate good which is God, there is the possibility of choosing between good and evil, and thus of growing in perfection or of failing and sinning. This freedom characterizes properly human acts. It is the basis of praise or blame, merit or reproach.
In short, we are predestined to do the will of God, but we have the free will to reject God and not do what we are predestined to do.
Predestination in the Catholic sense is much less strict that in the Calvinist sense. The Catholic view acknowledges both sides much more than Calvinism.
Footnotes:
395 Acts 4:27-28; cf. Ps 2:1-2.
396 Cf. Mt 26:54; Jn 18:36; 19:11; Acts 3:17-18.