Such watches - which are sold by a large number of providers in Germany - are generally aimed at children between the ages of five and 12.
Most are equipped with a Sim card and a limited telephony function and are set up and controlled via an app.
In October, the Norwegian Consumer Council (NCC) reported that 'some children's watches - including Gator and GPS for kids - had flaws such as transmitting and storing data without encryption.
It meant that strangers, using basic hacking techniques, could track children as they moved or make a child appear to be in a completely different location.
It is not clear whether the German decision to ban such devices was based on the privacy issues associated with them or wider security flaws that have been uncovered by NCC and others.
Both firms said that they had resolved the security issues.
Finn Myrstad, head of digital policy at the NCC said: "This ban sends a strong signal to makers of products aimed at children that they need to be safer."
He called for Europe-wide measures to increase the security of such devices.
Germany bans children's smartwatches - BBC News
Most are equipped with a Sim card and a limited telephony function and are set up and controlled via an app.
In October, the Norwegian Consumer Council (NCC) reported that 'some children's watches - including Gator and GPS for kids - had flaws such as transmitting and storing data without encryption.
It meant that strangers, using basic hacking techniques, could track children as they moved or make a child appear to be in a completely different location.
It is not clear whether the German decision to ban such devices was based on the privacy issues associated with them or wider security flaws that have been uncovered by NCC and others.
Both firms said that they had resolved the security issues.
Finn Myrstad, head of digital policy at the NCC said: "This ban sends a strong signal to makers of products aimed at children that they need to be safer."
He called for Europe-wide measures to increase the security of such devices.
Germany bans children's smartwatches - BBC News