Snail mail is a derogatory retronym (named after the snail with its proverbially slow speed) used to refer to letters and missives carried by conventional postal delivery services, and refers to the inevitable lag-time between dispatch of a letter and its receipt relative to the virtually instantaneous despatch and delivery of its electronic equivalent, e-mail.

It is also known, more neutrally, as paper mail or land mail.

Storage of paper mail is more difficult due to the fragility of paper. The difference in each envelope's size and fluffiness of the letters mean that they require a relatively large space storage for an extensive letter-writer.

There are efforts to renew interest in paper mail, such as the creation of mail art - physical art that is distributed and swapped around the world. An example of this is Nervousness.org, an organization of artists who create LMAOs, or Land Mail Art Objects (not to be confused with the Internet acronym LMAO, or Laughing My Ass Off), which are then swapped by post. Various forms of LMAOs include Artist Trading Cards (or ATCs), zines, decos, and many more. The Snail Mail World Postcard Art Show is one of the largest of its kind, drawing in up to 1000 entries each year.

Some online groups also use paper mail through regular gift or craft hot topics.

In the USA, LetterWise is an E-mail to paper mail service for those unable to receive email, such as the elderly. In the UK, Royal Mail offers a similar service.