New guidance coming into effect in November will mean admission to Communion - the sharing of bread and wine - will open to a much larger group.
The Church said it was to strengthen ministry to children and young people in particular.
Currently people wishing to receive Communion have to be confirmed first - confirming promises made on their behalf at their baptism as infants.
From the First Sunday in Advent - November 27 - this will no longer apply and everyone who has been baptised will be able to receive Holy Communion.
The policy will be rolled out across the parishes and ministry areas over the next year.
Announcing the change in a pastoral letter, the Church's bishops said: "In the Church today, there are many who believe that the witness of the Church to Jesus Christ, and the process of nurturing children and young people in the Christian faith, would be immeasurably strengthened by recovering this earliest symbolism.
"Baptism alone should be seen as the gateway into participation in the life of the Church, including admission to the Sacrament of Holy Communion.
"In conjunction with advice from the Doctrinal Commission of the Church in Wales, and from the Governing Body, the Bench of Bishops wishes now to re-adopt the practice of the early Church with respect to admission to Holy Communion.
"It is our conviction that all the baptised, by virtue of their Baptism alone, are full members of the Body of Christ and qualified to receive Holy Communion."
The bishops said the policy would lead to a strengthened understanding of the rite of Confirmation.
"It will be no longer the gateway to Communion, but take its proper place in the sacramental acts of the Church as a channel of God's grace, affirming disciples of their place in the fellowship of the Church and commissioning them for service in the Church and world," they said.
