Happy Home Network Design Contest

The Happy Home Network Design Contest was a monthly event accessible from the Happy Home Network in. It ran from October 2015 to May 2017, and was run by King Nook. During its run, there was a new theme every month. Each contest included related items to use in the design, similar to DLC, which the player could use in later designs if they participated. Players could submit and vote on designs during the first half of each month, and the best designs were displayed on the Happy Home Network in the latter half.

As the contests progressed, more of the exclusive items were repeats of those used during previous contests. The October 2016 contest was the last one to include a "new" item (the Monitor Tower). From November 2016 to the final contest (May 2017), all exclusive items were repeats. The items distributed in this contest were later added to in the  update and can be purchased from the catalog if the player has  save data on their Nintendo 3DS.

List of themes
{| class="collapsible" align="center" width="80%" style="height:40px; background:#5ed5d1; border:3px solid #12C7B7; " ! style="padding:3px 0 0 0"|
 * style="border-top: 1px solid #16c6b8; padding: 5px 3px 2px 3px"|
 * style="border-top: 1px solid #16c6b8; padding: 5px 3px 2px 3px"|
 * }