To evaluate learning curves in pediatric flexible ureteroscopy (FURS) and pediatric prone percutaneous nephrolithotomy (PCNL) by a single surgeon with experience in adult endourological procedures.Children who were diagnosed with nephrolithiasis and treated with PCNL or FURS from June 2014 to April 2019 were analyzed. Patient demographics, stone characteristics, stone-free rate (SFR), complication rate (CR) were reported. Learning curves were generated to estimate the effect of a surgeon's experience on outcomes.Seventy-three children underwent PCNL on 86 sides in 77 operations and 275 children underwent FURS on 320 sides in 288 operations. The SFRs were 88.1% (282/320) for FURS procedures and 89.5% (77/86) for PCNL procedures. CRs were 19.8% (57/288) and 35.1% (27/77), respectively. Learning curves showed that the SFRs of the two procedures increased with the accumulation of cases. There was an apparent improvement of SFR for PCNL procedures after about 60 surgeries. A favourable SFR of FURS could be achieved at the start of learning. No apparently decreased CRs were observed for either PCNL or FURS.Both PCNL and FURS could achieve satisfactory SFRs and accepted CRs in paediatric stones. Increased surgical experience was associated with improved SFRs of both PCNL and FURS procedures and the surgeon's adult FURS experience translated to paediatric FURS better than adult PCNL experience translated to the paediatric PCNL. A surgeon needs approximate 60 cases of PCNL to achieve competence. For FURS, a favourable SFR could be achieved at the start of learning.