CAPCOM：MONSTERHUNTER 4 Ultimate Official Web Manual

When you add a player to your friend list, you'll be able to see their online status, and it'll be easier to find each other in Online Multiplayer. Furthermore, you can make it so that people on your friend list don't need to enter a passcode to join your Gathering Hall, even if it's passcode-protected to the general public. However, if a friend's Gathering Hall has a key icon, you will still need to enter a passcode to join.

*You cannot see your friends' online status during Local Play or Hunter Search.
*Friends registered in Monster Hunter 4 Ultimate will also be registered to your Nintendo 3DS system's friend list. To remove a friend you must do it from the System Settings.
*In order to become friends with another player, you must first make your Personal Mii. For more information, please refer to the Nintendo 3DS system's Operation Manual.
*If your system's friend list settings are set to not show your online status to your friends, you will always appear offline in Monster Hunter 4 Ultimate.

Friend Requests

Join the same Gathering Hall as the player you wish to send a friend request to. You cannot send a friend request to someone who is out on a quest.

Sending a Friend Request

①From the menu select Friends, or touch the Friends button located on the Touch Screen that is displayed when you're in Town. Then select Friend Registration.

②Check the name of the player you wish to befriend and then select Send.

Receiving a Friend Request

Choose whether to accept or deny the friend request.

*If you have not made your Personal Mii or if your friend list is full, you cannot accept any friend requests. Your friend list can hold a maximum of 100 people.