Baptism is the way in which a person is actually united to Christ. The experience of salvation is initiated in the waters of baptism.
Baptism and Chrismation (i.e. Confirmation) are the two rites of entry into the Orthodox Church. Baptism and Chrismation are two Holy "Mysteries".
Through baptism the believer partakes in the Death and Resurrection of Christ. Consequently, Baptisms are traditionally performed by a three-fold immersion into a baptismal font, which represents both the tomb of burial and resurrection, and the womb of the second birth into new life in Jesus Christ.
Source: The Ukrainian Orthodox Church of Canada