Claire Lim was born on October 24, 1996 to Polly and Rolando Lim and has two siblings. She was born to a family into association football ; her older sister Katherine would play for Boston University, and her older brother and uncle also played competitively in the sport. Lim started playing soccer when she was six years old though she also tried getting into dance and gymnastics. She graduated from Piedmont High School in California in 2014 and entered UC Santa Cruz to pursue a college degree in psychology. She both played for the soccer teams of her high school and university.
Lim played for the women's team of Piedmont High School receiving four varsity letters in soccer. She was named part of the Second Team All League in 2011 and the First Team All League in 2012 and 2013.