Activating your new Capital One credit card is a quick and easy process that ensures you’re ready to start using it right away. Whether it’s your first time with Capital One or you’re replacing an old card, you can activate it online, through the mobile app, or by phone. Here’s how I activated mine and what you can expect. When I received my Capital One card in the mail, I was excited but knew I had to activate it before using it. I decided to use the Capital One mobile app , which I already had installed. I simply logged in, tapped on my card, and followed the on-screen instructions. In less than a minute, my card was active and ready to go! Ways to Activate Your Capital One Card 1. Online (Using a Browser) Visit: www.capitalone.com/activate Log in using your Capital One credentials. Select the card you want to activate and follow the prompts. 2. Via the Mobile App Open the Capital One mobile app . Log in to your account. Tap your card and select "Activate...