Enrolment at the Greater Essex District School Board is greater than projected and more teachers have been hired.
Superintendent of education John Howitt said there are 440 more kids in class than expected.
"Over 300 of those students are all at the kindergarten levels - JK and SK. Normally, we have a better handle on those numbers from February and March enrolments," he said. "We didn't expect it to go up that much, and especially at the early years level."
Board spokesperson Scott Scantlebury said that people could have been waiting for labour dispute between teachers and the province to end and stabilize.
"People may have waited until the last minute to register to be certain that things were stable," he said in an email.
Howitt said the increase has allowed the public board to hire 23 additional teachers.
Enrolment figures at the high school level won't be known until next month.
"We had no layoffs ... in spring. These are all new hires," Howitt said.
Some new teachers were part-time contract teachers and others are from the occasional teachers list, Howitt said.