Hold Z and press start at the title screen to reveal ''Special Contests'' on the main menu. You will find it there.
Unlock "Cheep Cheep Tournament" Course
Complete the Lakitu Classic with any character to unlock the new course, Cheep Cheep Tournament.
Unlock "Sands Classic" Course
Complete the Cheep Cheep Tournament with any character to unlock the new course, Sands Classic.
Unlock better versions of the available players
In order to unlock the star versions of each player you must defeat them in a vs. character match when they have an envelope next to their character select symbol on the vs. screen. The star versions of the players can drive the ball a lot farther then their original counterparts
Unlock Birdie Challenge Back Nine
Just beat the front nine in the birdie challenge to unlock the back nine.
Unlock Boo
Get 50 Best Badges to unlock Boo.
Unlock Character "Bowser Jr."
Complete the ring shot mode entirely with any character to unlock Bowser Jr.
Unlock Character "Shadow Mario"
Collect Every Badge in Tournament mode to unlock Shado Mario. (You get badges by getting a Birdie or better on each hole, but you can only get one per hole, meaning, you can't keep playing the same hole over again and getting a badge)
Unlock Course "Blooper Bay"
Place 1st in the Sands Classic with any character.
Unlock Course "Bowser Championship"
Place 1st in the ''Peach's Invitational'' with any character.
Unlock Course "Peach's Castle Grounds"
Place 1st in the Blooper Open with any character.
Unlock Expert-Level Side Games
Simply clear an intermediate level side game, in order to unlock its harder counterpart.
Unlock Intermediate-level Side games
Simply clear the beginner level of a side game to unlock its intermediate level counterpart.
Unlock Petey Piranha
To unlock Petey Piranha you must beat the Shooting, Approching, and Putting side games on all 3 levels.
Special Contests
At the main title screen hold the Z button and press start. There should now be a selection called "Special Contests". From there, you can do a hole in one challenge, as well as password input:
Hollywood Video Tour: At the "Special Contests" section, enter the code BJGQBULZ
Target Tour Tournament: At the "Special Contests" section, enter the code CEUFPXJ1
Bowser's Big Blast
After unlocking the Password Tournament feature, type in 9L3L9KHR to get the tournament, Bowser's Big Blast, on Bowser's Badlands.
Peach Open
To unlock the Peach Open, at the main menu hold Z and press START. Then at the special tournaments page enter the code ELBUT3PX.
Change Weather
Save your game and then reload it. The weather is randomly generated each time the hole loads.
Pikmin at the Peach Invitational
During the Peach Invitational, if your ball lands in the yellow flowers you will hear a weird noise and see small Pikmin fly out screaming. Press B to see an instant replay of the action.
Quick Replay
Once your shot has stopped, press B to watch an immediate replay. The angle will change each time you view the replay. Press A to speed the ball up during the replay.
Reset Pin Location
Don't like where a pin is located? Save your game and when you load it up the pin will be randomly relocated.
Restart Hole
At any time in any one-player game mode that allows you to save (i.e. Tournament Mode, Character Matches), you can restart a hole you're doing poorly on. Save the game and when you reload you will begin at your drive and all uses of Power and all shots will be erased, giving you a second chance.
Super Spins
When setting the accuracy meter, there are four types of spins you can apply depending on your button combo press. You must enter the combo quickly:
A, B: Super topspin
B, A: Super backspin
A, A: Normal topspin
B, B: Normal Backspin
Taunt Your Opponent
If playing a multiplayer game (with multiple controllers), press any button or use the C-Stick when it isn't your turn to taunt the opponent. When you taunt you can either use the C-stick for nice taunts or the D-pad for evil taunts. This makes it easy to do multiple taunts for maximum annoyance of other players for when you want the others to screw up in really competitive games where heavy bets have been placed. Just roll your thumbs on the d-pad and c-stick and it will make their mind twist and flip.