(Pocket-lint) - Fitbit's been making trackers for people's children for some time, most notably in the form of its Ace line of trackers, now on the Ace 2, but it hasn't yet branched out into full smartwatches aimed at younger users.

While it's been moving in this direction for adults in the form of the Versa line, it's reportedly now also got plans on the smartwatch front, according to a report from Engadget.

It's apparently heard from sources close to the matter that this is the reason behind its acquisition of a startup from Hong Kong, Doki, which has made kids' smartwatches with video calling capabilities. 

Doki's range of products are being disconnected on 1 July, although there hasn't yet been a formal announcement of the acquisition, and it looks like the deal might have been completed just prior to Fitbit's own acquisition by Google, which will take some time to complete.

None of this means that Fitbit's ideas for a kids' smartwatch are close to fruition, of course, but another interesting facet of Doki's platform is the inclusion of a SIM card that gave cellular cover to users, meaning that there could be scope for Fitbit's eventual product to have 4G coverage of its own, rather than tethering to smartphone data as you'd more commonly expect. 

The market for children's trackers is ever-growing, much like the fitness tracker market in a wider sense, with parents enthused by the possibility of both keeping tabs on their kids' whereabouts and their activity levels, although enthusiasm is more widespread outside of Western markets, which will be a challenge for Fitbit to surmount. 

Writing by Max Freeman-Mills.