The broadcaster faces a two-pronged attack from ITV and the BBC. Last month, ITV said it plans to roll out in February a digital free-to-air children's channel, while the BBC's CBeebies is drawing audiences on Freeview.
The first new channel, Cartoon Network Too, will show old favourites such as Yogi Bear, Wacky Races and Hong Kong Phooey from the Hanna Barbera Library, as well as offering its target audience of children aged four to nine original programming developed by Cartoon Network.
Turner said the launch of Too will allow its flagship channel, Cartoon Network, to focus on new programmes.
The second channel, Boomerang +1, will launch in 2006. It is aimed at the whole family and includes classics such as Scooby-Doo and Tom & Jerry.
A spokeswoman for Turner Broadcasting said it was still in negotiations with networks to air the new channels.