There is a dearth of research in aquatic motor competency, a key requirement for primary physical education in order to become physically literate. This study proposes a new assessment protocol for aquatic motor competence and sets out to examine the validity of the Aquatic Movement Protocol (AMP) in children between 7 and 9 years of age. Testing of Gross Motor Development--second edition was implemented to assess general motor competence, including a composite of 10-m running sprint time and standing long jump distance. Aquatic motor competence was assessed by the AMP. Univariate analyses of covariance were used to examine whether assessment of general motor competence differed as opposed to aquatic motor competence. Process and product measures of dryland motor competence were analyzed using male and female subjects measuring three aquatic motor competences (low, medium, and high). Cronbach's alpha and exploratory factor analyses were implemented to show both construct and concurrent validity of the AMP. Children classified as high for aquatic motor competence had significantly higher general motor competence (p = 0.001). Those who achieved a higher composite score for faster sprint speeds and longer jump distances had significantly higher aquatic motor competence (p = 0.001). Cronbach's alpha of 0.908, showed internal consistency of the AMP. Results extracted one factor from analysis with an eigenvalue = 6.2; %variance = 62.1, with loadings higher than 0.5. This data suggests that the items on the AMP measure a single construct that we would call "Aquatic Motor Competence." This study demonstrates that the AMP is a valid measure of aquatic motor competence in primary aged children.