The longitudinal relations of domain-general and numerical skills at ages 6-7 years to 3 cognitive domains of arithmetic learning, namely knowing (written computation), applying (arithmetic word problems), and reasoning (arithmetic reasoning) at age 11, were examined for a representative sample of 378 Finnish children. The results showed that domain-general skills, including spatial visualization, language, rapid automatized naming, and working memory, contributed independently to arithmetic learning. These relations were mostly mediated via basic number competence (i.e., counting sequence and number system knowledge), although spatial visualization remained predictive of arithmetic outcomes. The findings underscore a similar developmental course of arithmetic learning across different cognitive domains where domain-general skills build a launchpad for advanced arithmetic via enhancing basic number competence.