In Final Fantasy X, Rikku is kind-hearted, spirited, happy-go-lucky, and energetic, which sometimes clashes with the more stoic group members. She looks up to Lulu as a role model, being impressed with her calm level-headed nature. Rikku tries to maintain a positive outlook but there is a stark contrast when she is upset, and despite her outwardly happy exterior, she carries some insecurities, particularly when it comes to her future and what she wants to be. Rikku is bilingual and skilled in chemistry and alchemy. She suffers from astraphobia (fear of lightning) after a mishap involving Brother and a stray Thunder spell in her youth, but has overcome it by Final Fantasy X-2 by camping out in the Thunder Plains for a week. Rikku is loyal to Yuna yet is the most vocal opponent to the ongoing pilgrimage. She bonds with Tidus, perhaps because of their similar personalities and devotion to Yuna.
In Final Fantasy X-2 Rikku continues to care about Yuna's welfare while encouraging her to have more fun in life. She has become Yuna's role model who copies her erratic behavior and unique expressions, though Rikku sometimes reprimands Yuna for using foul language. Rikku remains the ever upbeat and somewhat reckless individual, occasionally causing trouble for her friends.