- "I want to be friends with [Mii]."
- — Mii, Tomodachi Life
A friend is a relationship in Tomodachi Collection, Tomodachi Life, and Miitopia. When Miis become friends, they hang out with each other often, either talking to each other in their apartments, playing with different gifts, or going to different places. If two normal friends spend time with each other long enough, they could become best friends; if a Mii develops feelings for another Mii of the opposite gender, they could confess to them and begin to date. If they fight, this could cause them to stop being friends if it fails to be resolved.
Friendships are first introduced in Tomodachi Collection, as a relatively simple procedure. When a player enters a Mii's apartment, they will tell the player they want to become friends with another Mii, asking what they should do to get along with them. After choosing either option, the player will speak with the other Mii and will visit the other Mii's apartment. There, they talk for a few seconds, before waving as stars surround them. The Mii will be happy afterward, with the caption "It went great!", followed by the Mii saying, "It worked! We're friends now, thanks to you!". If they don't befriend each other, the stars won't appear, and the Mii will say "We're not quite friends yet..." afterward.
Friendships return in Tomodachi Life, functioning mainly the same as in Collection. However, the person the Mii wants to meet will no longer come to the Mii's apartment, and it instead occurs vice versa. The procedure is the same as in Collection after that point.
In addition, the Mii may hear from another Mii that they want to be friends instantly. If this happens, the Mii will tell the player that they heard that Mii wants to be friends. If the player says yes, a cutscene similar to the regular befriending scene will play, only in this one, the other Mii will answer the door for the asking Mii before they talk with each other, sometimes standing in the middle of the room, watching the door, or skipping around before the Mii arrives. If they become friends, they wave as the stars appear and the "ding" plays, and the Mii will be happy afterward, saying "We're friends now!"; if they don't become friends, the Mii will say, "We didn't really click, so we didn't become friends this time." or "We're not friends yet...". The Mii who answers the door will do things by the following personality.
A rare occurrence in the game is that Miis can befriend each other without player request; the player can see the two Miis talking to each other outside either apartment.
At times, a Mii might also want to introduce two of its friends to each other, the opposite Mii whom the first friend isn't friends with yet. When the player agrees, the Mii will ask what they should talk about to help the Miis get along. After choosing an option, the Mii will invite the two Miis over and a cutscene plays. The Mii will introduce the two Miis to each other, and they will begin talking. The conversation lasts a little longer than the cutscene of a Mii making friends with someone. During the conversation, the Miis will laugh, either one laughing or everyone looking surprised before bursting into laughter, the opposite Mii will be confused, or the introducing Mii will have to help them out. At rare times, the two Miis might talk at the same time.
Friendships return in Miitopia, functioning much differently from the main Tomodachi games. Rather than the Miis requesting friendships, the player can place two Miis together in a room within an Inn, sometimes interacting with one another. If there is good chemistry between the two Miis, their friendship level will increase. This can also happen outside of Inns, such as when a Mii helps out another Mii in a kind fashion.