Punahou School is losing its longtime high school and junior school principals after next school year — one to retirement and the other to a mainland school.

Punahou Junior School (kindergarten to eighth grade) Principal Mike Walker will be taking a new job as head of school at San Francisco Day School, effective July 1, 2015.

The school said Walker, who was hired in 1998 as principal of the elementary and intermediate grades, will finish out the 2014-15 school year at Punahou.

The independent San Francisco school announced Walker’s appointment on its website last week and quoted him as saying, "I am thrilled and honored to be invited to lead a school community so focused on the needs of its students, the engagement and support of faculty, and the involvement of the parents."

Meanwhile, Punahou Academy Principal Kevin Conway will retire after next school year. He joined the private school’s administration as high school principal in 2000.

A Punahou spokeswoman said the school is working on a plan to ensure a smooth transition. President Jim Scott was traveling Thursday and unavailable for comment.

Punahou is one of Hawaii’s largest private schools, with 3,750 students. Tuition is scheduled to increase to $20,700 this fall, up $750 from the year that just ended.

Saint Louis School also announced administration changes this week.

Saint Louis President Walter Kirimitsu will serve as head of school for the all-boys school next year, filling a newly created position that merges the president and principal posts.

The Kaimuki school’s principal position had been vacant since Pat Hamamoto retired in December. The former superintendent of Hawaii’s public schools had served as Saint Louis’ principal for four years.

The school said Kirimitsu, a former Appeals Court judge who has been the school’s president since 2005, is postponing his planned retirement for a year to serve in the headmaster position.

Saint Louis made headlines last year as it faced serious financial troubles before its alumni association agreed to back a financial plan to ease the school’s debt burden.

The school said it was forced to take out loans in recent years amid declining enrollment and unexpected facility costs.

Enrollment at the Catholic school had dropped significantly after peaking at 820 students during the 2007-08 school year. Saint Louis had 540 boys enrolled in grades 6 to 12 last year.

Still, the school’s board of trustees voted not to increase tuition for the coming year, keeping it at $13,322.