How to set the PIN on your Mastercard. Credit Cards: 844.334.3874 (the number on the back of the card) Option 7 and follow the prompts Debit Cards: 800.472.3272 (number on the back of the card) or 800.992.3808 (card self-service) Option 1 for activation and follow prompts Have more questions? Submit a request 0 Comments Article is closed for comments. Related articles How do I receive a PIN (Personal Identification Number) for my Mastercard credit card so I can access cash? Will I receive a PIN (Personal Identification Number) so I can access cash with my debit card? Why is my 3Rivers debit or credit card being declined? Vacation Mastercard debit card or Mastercard Credit Card was lost or stolen. Who should I call?