The events of Avatar: The Last Airbender begin six years thereafter, when Katara and Sokka find Aang in suspended animation and identify him as the Avatar, a messianic figure.Bent on mastering Waterbending, Katara joins Aang to reach the Northern Water Tribe to find a Waterbending master, with Sokka alongside them.
Katara and Aang are also revealed to have had three children: the non-bender Bumi (who later acquired the ability to airbend), the waterbender Kya, and the airbender Tenzin.
She plays a rather minor role in the first season of the series, only giving Korra her blessing to leave for Republic City to train with Tenzin and attempting to unsuccessfully heal her after she lost her waterbending, firebending and earthbending abilities to Amon.
In the second season's first episode "Rebel Spirit", Katara is seen celebrating with all three of her children at the Southern Water Tribe's Glacier Spirits Festival.
While together with them, Katara, holding her new grandson Rohan, watches sadly as she notices Kya and Bumi joking at Tenzin's expense.
Later, she offers to teach Katara a Waterbending technique called "Bloodbending", which enables physical control of animals and humans.
When Katara refuses to learn this technique, Hama uses it on Aang and Sokka, forcing Katara to use the technique herself on Hama.
At an Earth Kingdom stronghold, General Fong places Katara’s life in danger to induce Aang's Avatar State; but achieves only destruction.
After the earthbender Toph Bei Fong joins the group to teach Aang, Katara and Toph initially quarrel; but thereafter become friends.
In Light in the Dark, she is seen listening to Avatar Korra addressing the independent Southern Water Tribe and how she decided to have spirits and human coexist by leaving the spirit portals open.