The optimal time to bolus insulin for meals is challenging for children and adolescents with type 1 diabetes (T1D). Current guidelines to control glucose excursions do not account for individual differences in glycaemic responses to meals. This study aimed to examine the within-and between‐person variability in time to peak (TTP) glycaemic responses after consuming meals under controlled and free‐living conditions. Participants aged 8–15 years with T1D ≥ 1 year and using a continuous glucose monitor (CGM) were recruited. Participants consumed a standardised breakfast for six controlled days and maintained their usual daily routine for 14 free‐living days. CGM traces were collected after eating. Linear mixed models were used to identify within‐ and between‐person variability in the TTP after each of the controlled breakfasts, free‐living breakfasts (FLB), and free‐living dinners (FLD) conditions. Thirty participants completed the study (16 females; mean age and standard deviation (SD) 10.5 (1.9)). The TTP variability was greater within a person than the variability between people for all three meal types (between‐person vs within‐person SD; controlled breakfast 18.5 vs 38.9 minutes; FLB 14.1 vs 49.6 minutes; FLD 5.7 vs 64.5 minutes). For the first time, the study showed that within‐person variability in TTP glycaemic responses is even greater than between‐person variability.