To activate a Credit One card, call customer service at (877) 825-3242. It is not possible to activate a Credit One card online. The activation phone number will also be printed on the decal affixed to the front of the new card. As a security measure, Credit One recommends calling from the telephone number that you listed on your application. You will have to provide that number to customer service, anyway, if you call from a different phone.
When you call, enter your 16-digit credit card number. Because the number is for a card that has yet to be activated, the call will automatically route to the Credit One card activation menu. You can use either the voice automated system or, when prompted, connect to a customer service representative. You will then need to provide your birth date, your Social Security number (SSN) and the card's 3-digit security code.
Credit One does not provide an instant card number to use before the card arrives, which is usually around 10 business days after you're approved. When you receive the card, you won't be able to make any transactions on it until you activate it. Once activated, your Credit One card will be immediately available for use.
There is a deadline to activate, however. Credit One may close the account if you do not activate your new card within 14 days after you receive it in the mail. If this happens, you will not be able to reopen the account; you will have to re-apply for a new card.