WA Labor will trial free kindy five days a week at 10 schools across the State if they are re-elected.
The $33.8 million plan will begin at five regional schools and five metro schools in 2027.
If successful, the program will be rolled out at further schools across WA.
"I know the current five-day kindy fortnight can be tough for working parents, who are often spending hundreds of dollars a week on childcare to make up the difference," Mr Cook said.
"That’s why a re-elected WA Labor Government will roll out free full-time, school-based kindy - to give WA kids the best possible early education."
Currently, WA children can attend kindy 15 hours per week.