Those in acting roles will be placed in those positions for two terms, with permanent principal vacancies advertised at the end of term 1, to begin at start of term 3.

Tasmanian Principals Association president David Raw said movement by principals could be attributed to natural employment processes, such as retirement of older teachers.

"There are a lot of people who are 55 or 60 and this was always going to happen," he said.

Tasmanian Association of State Schools Organisation president Jenny Eddington said when one principal retired or left their job, it created a domino effect across the state.

She said principal turnover was a statewide occurrence.

"I'm not unsympathetic of the situation, but it is very disruptive to schools," she said.

"This year it will be even more disruptive because a lot of schools don't know who their teachers are going to be next year, so at the start of the year it will be a real challenge for staff."

Retiring principals included Riverside High's Christine Males and Trevallyn Primary's Cheryl McFadzean, with Ravenswood Heights' principal Britany Roestenburg heading for Darwin.

The Riverside position will be filled by the principal from Lilydale District School, believed to be Greg Morgan, the Trevallyn position will be filled by Cressy District School's Annette Hollingsworth, and the Ravenswood Heights position will be filled by the former Meander Primary's principal Zach Taylor, all in acting positions.

Other schools impacted include Deloraine High, Invermay Primary and St Helens District High.