Aang is a twelve-year-old Air Nomad and the last surviving member of his people. He has a small, athletic build, light skin, gray eyes, and a distinctive arrow-shaped tattoo running from his forehead down his scalp and back. He is usually dressed in traditional orange and yellow Air Nomad clothing, often accompanied by his staff and his flying bison, Appa. Aang is cheerful, playful, adventurous, and naturally curious, frequently approaching dangerous situations with an optimism that contrasts with the seriousness of the world around him. Despite his carefree personality, he carries the enormous responsibility of being the Avatar and struggles with the loss of the Air Nomads and the expectations placed upon him.

Sokka is a teenage warrior from the Southern Water Tribe and Katara's older brother. He has a sturdy, athletic build, tan skin, dark hair that he usually keeps in a short warrior's style, and a distinctive Water Tribe outfit consisting primarily of blue and gray clothing. Unlike most members of Team Avatar, Sokka is not a bender. Instead, he relies on physical training, weapons, engineering, observation, and strategic thinking. Sokka initially presents himself as confident, sarcastic, and occasionally boastful, frequently providing comic relief through his dry humor and exaggerated reactions. Beneath that humor, however, he is deeply protective of his friends and takes his responsibilities as a warrior seriously. As the journey progresses, Sokka becomes the group's primary strategist, learning to compensate for his lack of bending through planning and creativity. He develops his skills as a fighter and eventually becomes proficient with a sword. Sokka's intelligence is one of his greatest contributions to Team Avatar: while Aang and the others can often solve problems through bending, Sokka frequently approaches situations by analysis.

Zuko is the exiled prince of the Fire Nation and one of the series' most important characters. He has pale skin, dark hair, amber-colored eyes, and a prominent burn scar covering the left side of his face. His clothing is usually based around the red, gold, and dark colors associated with the Fire Nation, although his appearance changes as his circumstances and personal identity develop. Zuko initially appears angry, intense, impatient, and obsessed with capturing the Avatar because he believes doing so will restore his lost honor and allow him to return home. However, beneath his hostility is a deeply conflicted teenager struggling with his father's expectations, his complicated family history, and his own understanding of right and wrong. Zuko is a highly capable firebender, trained from childhood in both bending and martial combat. His firebending is aggressive and powerful, but his greatest development comes from learning where his strength actually comes from and separating his identity from the approval of his father.

Katara is a young waterbender from the Southern Water Tribe and the younger sister of Sokka. She has brown skin, blue-gray eyes, and long brown hair that she commonly wears in two looped braids with Water Tribe clothing in shades of blue. Katara is compassionate, determined, passionate, and strongly motivated by her desire to protect people and stand against injustice. She often acts as the emotional heart of Team Avatar, encouraging her friends when they are struggling while also being willing to challenge them when she believes they are making the wrong decision. Katara begins the series with relatively limited waterbending experience but possesses tremendous potential and gradually becomes a highly skilled waterbender. Her abilities eventually expand beyond ordinary water manipulation as she learns advanced techniques and develops greater control over her element. She is also an excellent healer, using waterbending to treat injuries.

Toph Beifong is a young blind earthbending master who becomes Aang's earthbending teacher and joins Team Avatar. She has a short, compact build, pale skin, and dark hair usually worn in a distinctive bun-like style. Her traditional Earth Kingdom clothing is primarily green and beige, with her feet playing an especially important role in her bending because she uses contact with the ground to sense vibrations around her. Toph is blunt, stubborn, confident, competitive, and fiercely independent. She dislikes being treated as fragile because of her blindness and has spent much of her life proving that she is capable of taking care of herself. Rather than viewing blindness as something that prevents her from fighting, Toph has developed an extraordinary form of sensory perception through earthbending, allowing her to detect movements and objects through vibrations in the ground.

Suki is a skilled warrior from Kyoshi Island and the leader of the Kyoshi Warriors, an elite group of female fighters who follow the traditions and ideals of Avatar Kyoshi. She has dark hair, brown eyes, and typically wears the distinctive green and yellow armor, makeup, and clothing associated with the Kyoshi Warriors. Unlike Aang, Katara, Zuko, and Toph, Suki is not a bender. Instead, she relies on martial arts, agility, strategy, and specialized Kyoshi Warrior equipment. Suki is confident, disciplined, courageous, and responsible, but she is also capable of being warm and playful outside of combat.