Effective learning methods are essential for motor skill development and participation in children with low motor abilities. Current learning methods predominantly aim to increase declarative knowledge through explicit instructions that necessitate sufficient working memory capacity. This study investigated the roles of declarative knowledge and working memory capacity in explicit motor learning of children with low motor abilities. We studied both acquisition performance (i.e., performance during practice) and learning (i.e., the improvement in performance from pretest to posttest). After practice with explicit instructions, children with low motor abilities showed significant learning, albeit that improvement was relatively small. However, working memory capacity and declarative knowledge did not predict learning. By contrast, working memory capacity and declarative knowledge did predict performance during practice. These findings suggest that explicit instructions enhance motor performance during practice, but that motor learning per se is largely implicit in children with low motor abilities.