Smartphones have become so common that many parents now buy one for a child at primary school age. While I accept that parents have legitimate reasons for wanting to stay in contact with their children, I largely agree that those under twelve should not have a smartphone of their own.
The main argument for this view is that a smartphone gives a young child access to far more than they can handle. With an internet connection, a child can come across violent or inappropriate material, be contacted by strangers or be drawn into online arguments with classmates. Even when parental controls are installed, determined children often find ways around them. There is also the question of habit. Games and video apps are designed to hold attention for as long as possible, and a nine-year-old has very little ability to stop voluntarily. A child who spends every evening scrolling may sleep less, read less and spend less time playing outside, all of which matter greatly at that stage of development.
Opponents argue that a phone keeps children safe, because parents can call them or track their location as they walk home. This is a reasonable concern, but it does not require a smartphone. A basic handset that can only make calls and send text messages provides the same reassurance without the distractions and risks of the internet. Some families also allow supervised use of a shared tablet at home, which lets children learn digital skills in a controlled setting rather than alone in their bedroom.
In conclusion, I believe that delaying smartphone ownership until around the age of twelve is a wise policy for most families. Children can still be reachable and digitally capable, but they are protected from pressures that they are not yet ready to face.