StreetPass

StreetPass is a feature present in every Nintendo 3DS system that allows users to exchange data from games & applications that the two own. It is on regardless of whether the 3DS is in sleep mode or not (though the system itself must be on), and automatically acts when another 3DS user walks within the console's range. With it, players can acquire new features in games that they own (even if the game's card is not presently in the 3DS card slot) and obtain the Miis of 3DS users that walk past them. If one wishes, they can turn the feature off completely or assign the games that they want it to work with. Several games have made use of this function in unique ways. Other content that can be transmitted include puzzle piece for Puzzle Swap, messages from the user (in addition to their favorite game on the system), and their most played song with Nintendo 3DS Sound.

The LED notifier of the upper right side of the Nintendo 3DS (when closed) alerts players when data has been exchanged with another user whether it be through StreetPass or SpotPass with a blinking green LED color.

List of games
Note: This list is not complete.

The following are a list of games that use StreetPass.

Preloaded games
Nintendo developed two games that come preloaded onto every 3DS system that showcase the StreetPass’ capabilities of the handheld. These games, called Find Mii and Puzzle Swap, revolve entirely around StreetPass. In Find Mii, users attempt to rescue a king trapped in a castle by enlisting new party members. This can only be done by passing by other 3DS owners and acquiring their Miis (new party members can also be acquired by using Play Coins, and they appear as Mii Dogs or Cats, depending upon the user’s selected favorite). In Puzzle Swap, players gain puzzle pieces by passing other users on the street. Once a puzzle is complete several things may happen, such as the image turning into a short movie or a trophy that can be manually maneuvered (similar to Super Smash Bros. Melee and Brawl, and as shown in the E3 2010 demostration of the Nintendo 3DS). Several of the images are of classic Nintendo characters such as Mario, Samus, Link, Kirby and the Pikmin, as well as secondary characters from those video game series such as Bowser, Luigi and Yoshi. Each 3DS user is assigned a default puzzle, with other puzzles available only through StreetPass swaps. Users who do not use StreetPass can acquire puzzle pieces to an already started puzzle by using Play Coins. You can also purchase Mii Force, Flower Town, Warrior's Way, and Monster Manor in the game by going to the bunny of the game you want to purchase. You can purchase them individually, or save roughly $5 by purchasing them in a bundle.

Origin
A couple of Nintendo DS video games featured a similar feature. Nintendogs ' Bark Mode and Dragon Quest IX: Sentinels of the Starry Skies ' Tag Mode both function in a similar manner yet require that the game's cartridge be placed in the system and the mode manually activated. According to Nintendo 3DS producer Hideki Konno, the feature was implemented in the Nintendo 3DS primarily because of the overwhelming success of Dragon Quest IX, particularly in Japan. Konno also revealed that his son was somewhat bored with the similar feature included in the original Nintendogs, emphasizing the importance that Dragon Quest had on the inclusion of StreetPass in the Nintendo 3DS.

Kingdom Hearts: Re:Coded for the Nintendo DS also features a tag mode similar to the one in Dragon Quest IX.

The Unknown Dungeon in Pokémon Mystery Dungeon: Blue Rescue Team permited players to put the Nintendo DS to Sleep Mode while keeping the Wireless Swich on. Players who passed other players of this game that are in the Unknown Dungeon in this fashion can send their Pokémon to the Unknown Dungeons of other players and bring back items.

The World Ends with You has a Mingle mode that levelled up the pins of the player if the player passed other users of the Nintendo DS with the Wirless Swich on, wether the player is playing The World Ends With You or not.