International Pen Friends
- Established in April 1967, membership has grown to over 1.5 million worldwide. Individual and school applications are available.
- http://members.ozemail.com.au/~penpals/

PostcardX
- Postcard exchange site that encourages sending kindness to random members.
- http://postcardx.net

Penpals Cafè
- A free snail mail penpal service.
- http://web.tiscali.it/penpalcafe/

SAPE
- Matches people with penpals in the former USSR and Baltic countries. Applications by snail mail only
- http://www.michander.com/sape/

The Letter Exchange - A Magazine for Letter Writers
- Anonymous pen pal listings in 35 categories like Daily Life, Literature, and Ghost Letters (writing as imaginary characters). Subscription includes confidential forwarding.
- http://www.letter-exchange.com

Dolphin International
- A quarterly printed magazine for penpals, marriages, and snail mail friends.
- http://www.dolphin-intl.com/pmag.htm

Peter's Penpal Club
- Privately register for a free personalized penpal match.
- http://www.snowpals.de/penpals

Global Penfriends
- List your information for free for others to contact you, or join Global Penfriends to select your own penpals.
- http://www.penfriends.com.au

WCF's International PenFriends
- A non-profit cultural and educational organization based in the USA that has grown to over one million members in over 251 countries and territories around the globe.
- http://www.wcf.org/penfriends.htm