Foden, who was head of one Gwynedd school and strategic head of another, was also found not guilty of one count of sexual activity with a fifth girl during his trial in May.
The teacher joined Ysgol Friars in Bangor, Gwynedd, as a deputy head in 1989, becoming headteacher in 1997.
He was also strategic head of Ysgol Dyffryn Nantlle secondary school in Penygroes.
Five girls, who cannot be identified, accused him of abuse between January 2019 and September 2023.
Across the three-and-a-half week trial, the court heard how the head teacher groomed and abused the youngsters over a four year period, in locations including his car and hotel rooms.
