- "I want to be friends with <Mii>."
- — Mii, Tomodachi Life
A friend is a relationship in Tomodachi Collection and Tomodachi Life. 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 establish a Sweetheart relationship.
If a Mii wants to befriend another Mii, it will have an orange problem icon on their apartment window. Upon entering and tapping their thought bubble, the Mii will tell the player they want to be friends with a Mii of their choice. If the player agrees, the Mii will ask the player what they should talk about:
- Something funny
- Deep thoughts
- Something serious
Sometimes the Mii might ask the player what it should do to help them get along:
- Be flattering
- Try to listen
- Keep it brief
- Be polite
After choosing either option, a cutscene follows. The Mii will visit the other Mii's apartment, and they will talk for a few seconds. If the Miis befriend each other, they will wave as stars surround them, as a "ding" sound plays. 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!". But if they don't befriend each other, the stars won't appear, and the Mii will say "We're not quite friends yet..." afterward.
Sometimes the Mii will 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.".
Rarely, the Miis befriend each other without player request; the player can see the two Miis talking to each other outside either apartment. When befriending, they wave as the stars appear and "ding" sounds, and the caption, "<Mii 1> and <Mii 2> became friends!" appears.