Purpose. the aim of this study was to compare the level of declarative tactical knowledge between U-11 and U-15 academy players. Methods. the sample comprised 36 U-11 (n = 18) and U-15 (n = 18) soccer players, with practice time of 1404.00 ± 469.52 hours and 2663.55 ± 594.91 hours, respectively. the players' practice time was collected through a recording questionnaire. Declarative tactical knowledge was assessed through a verbal report used during a video simulation test. the answers provided during the test were scored as follows: best solution (1 point); second best solution (0.75 points); third best solution (0.50 points); fourth best solution (0.25 points); wrong solution (0 points). For statistical analysis, descriptive analysis was performed, as well as the Shapiro-Wilk and Mann-Whitney tests, with significance level set at p < 0.05. For statistical purposes, the SPSS 22.0 software was applied. Results. Significant differences were observed in declarative tactical knowledge between the U-11 and U-15 age groups. Players of the older age group displayed longer practice time and higher scores than their younger counterparts. Conclusions. Players with longer practice time (U-15) possess greater declarative tactical knowledge than those with less practice time (U-11), and declarative tactical knowledge is a factor that differentiates soccer players aged 11 and 15 years.