Message bottle

A Note-in-a-bottle will sometimes wash up on the beach in, but can be obtained in if a player moved from their Wild World town and had one in their catalog. They will all say something different.

The player can also buy bottles in Tom Nook's store for 200 Bells each and unlike most items have unlimited stock. If they write something inside them and release them, and a friend has done the same, when the two connect through Contact Mode/Tag Mode, they will each find afterwards their friend's note-in-a-bottle washed up on their beach, as well as both having each other's constellations. They can be saved in the Town Hall like Letters. You can also send presents a long with the notes, but it is unknown if they reach the other end.

Trivia

 * You can tell if the mail is from a real person or Nintendo, as a note from a real player will always start with "Dear Some Stranger", unlike a Nintendo note-in-a-bottle.