Visit GreenDot.com/activate or tap Activate Now in the Green Dot app or call (866) 795-7605. Excludes temporary cards acquired at a financial service center (location offering check cashing, payday loans, money transfers)​ 2. Enter all info requested, including personal info and card details: Name Address Date of birth Social security number 16-digit card number Expiration date 3-digit security code (found on the back of your card) Mobile phone number 3. Start using your card upon successful activation. Please provide the most up-to-date address and mobile number. If you are having issues activating your account, call (866) 795-7605 or check the Quick Help Guide for easy step by step instructions. We’re required to collect this information in accordance with The USA PATRIOT Act — a Federal law that requires all financial institutions to obtain, verify and record information that identifies anyone who successfully opens an account with us.