In a thread on NeoGAF, it has been said that Pikmin 3 developer, Shigeru Miyamoto, has said the following to Shigesato Itoi about the future of the game:
So, using the internet [the team] thinks it’d like to add new missions and maps to the game little by little.
The game hasn’t been released yet in Europe or North America, and this is the first time DLC has been mentioned for the game. However, DLC for New Super Mario Bros. U seeming came out of nowhere, so I feel it is possible that we may see DLC for Pikmin 3. Things such as new multiplayer maps and missions could come by the way of DLC.
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