capital.one activate debit is the most convenient way to activate any new Capital One credit card. After going to capitalone.com/activate, enter your card details, complete verification, and your card will be fully activated. capital.one activate debit allows customers to activate their cards from the comfort of home. Simply open capitalone.com/activate, log in securely, and complete the quick activation process to access your account benefits. capital.one activate debit makes it easy to start using your Capital One card right after receiving it.