Some schools will have permanent 30kmh limits around them and others will have 30kmh limits that apply at times when pupils are being picked up and dropped off or they are walking and cycling to and from school.
Signs marking the beginning and end of school zones were being installed and the job should be finished by the end of July, the Dunedin City Council said.
Public consultation was carried out last year and a hearing was held in March.
The changes were then approved.
Many schools will have variable limits, which means the 30kmh zones will apply only near the start and end of the school day, or if there is another time children cross the road.
The rationale for lowering the limits was mostly connected to areas around schools being busy and slower travel speeds gave everybody more time to react to reduce the risk of serious injuries.
"With the support of the Dunedin community we are ready to implement the speed limit changes and make sure schools are safer for tamariki and their families," council transport strategy manager Nick Sargent said.
The council would work with police, Waka Kotahi NZ Transport Agency and communities to ensure a smooth transition to the adjusted limits.
The third school term starts on July 17.
Permanent 30kmh limits were also approved for four urban centres — Mornington, Māori Hill, Caversham and the tertiary-education precinct.
