For a list of postcards, see List of Postcards.
Postcards are cards that can always be sent to other players, and bought for 10 coins each, in the Post Card Catalog. The categories for post cards are invitations and encouragements. Some post cards are related to Club Penguin's theme for the month. Other invitations include the Pizza Parlor, the Coffee Shop, the Dance Club, the Snow Forts, the Ice Rink, Sled Racing, the Ski Lodge, Mancala, Cove, and Find Four. New postcards come out at least every two months. Since Penguin Mail was introduced, people can save their mail inside a "mailbox" and receive it even when they're offline. Non-Members can only have up to 50 postcards, however Club Penguin can add more. You earn salaries through postcards.
- It is impossible to get more than 92 postcards. If you get 93, the earliest postcard will be deleted and you'll still have 92.
- Only four postcards have free items in them: The Happy Holidays postcard (2009, 2010 and 2011) and the Penguin Mail postcard (sent by Club Penguin in July 2008).
- The 'penguin name' aspect of postcards is in text format rather than being part of the picture due to it being a variable.
- Penguins that weren't Secret Agents can still join the Elite Penguin Force by recieving a special postcard.
The Coffee Shop postcard.
The Beach postcard.
The Ice Rink postcard.
The Cool Igloo postcard.
The Dance Party postcard.
The Card-Jitsu postcard.
The Membership postcard.
The Ski Hill postcard.
The Dojo postcard.
The Adopt A Puffle Postcard.
The Elite Penguin Force Salary Postcard.