All Working Mario Tennis 64 Cheats - Nintendo 64

All characters and courts
Note: This does not unlock the Mario's Star court, and will delete all your saved accomplishments; it marks all of the goals as completed, including a gold star on all of the Ring Shot challenges. Press [Down]x2, [Left]x3, [Right]x3, [C-Down]x2, [C-Left]x3, [C-Right]x3 when "Press Start" appears at the title screen. A sound will confirm correct code entry.

Nintendo Ring tournament
Press [Start] at the title screen. Highlight the letter S (Special Games) in the center of the bottom row and press [A]. Highlight the trophy (Ring Tournament) icon, which is the third from the left and press [A]. Enter "A3W5KQA3C" as a password to play a tournament for the Mario Cup. Another password will be displayed after completing the tournament. The new password is not actually a password for the game, but is for ranking you with other players at Nintendo's Mario Tennis web site. Other passwords include the following.

Enter "J6M9PQJ6U" as a password to play for the Nintendo Power Cup.
Enter "ARM6JQARU" as a password to play for the Blockbuster Cup.
Enter "V2UFMPUZM" as a password to play for the IGN64 Cup.
Enter "V5UFMPU5M" as a password to play for the Pokemon.com Cup.
Enter "48HWOR482" as a password to play for the MarioTennis.com Cup.
Enter "M1C2YQM1W" as a password to play for the Luigi Cup.
Enter "LA98JRLAR" as a password to play for the Waluigi Cup.
Enter "UOUFMPUOM" as a password to play for the Wario Cup.
Enter "MM55MQMMJ" as a password to play for the Donkey Kong Cup.
Enter "OF9XFQOFR" as a password to play for the Peach Cup.
Enter "N24K8QN2P" as a password to play for the Bowser Cup.
Enter "4YHWOR4Y2" as a password to play for the Mr. Pickle's Cup.
Enter "ZKZLZKNNR" as a password to play for the Yoshi Cup.
Enter "5G3LTQ5GN" as a password to play for the WimbleDonkey Kong Cup.

Star player/handicaps
Note: Win the Star Cup with a character (get three cups in a tournament). Hold [R] while selecting that same character to make him have handicaps and make him more powerful. A yellow star will appear in the bottom right of the screen (for player one) or bottom left of the screen (for player two). Press [L] + [R] to have a left-handed player that is also a star character. Being a star player will enable you to serve stronger and play better. If you make Bowser a star player he will be able to serve up to 136 mph. Note: Donkey Kong Jr. and Shy Guy are already star players when they are unlocked.

Slow shot
Press [B], then [A].

Control the ball
This trick can be done with any player, against any player. Hold [Analog-stick Left] or [Analog-stick Right] as you hit the ball. This will send it in whichever direction you pushed the stick.

Shy Guy
Win the Star Cup/Singles Tournament. This character can already use the handicap cheat after being unlocked. You do not have to win the Star Cup as this character.

Donkey Kong Jr.
Win the Star Cup/Doubles Tournament as any character. This character can already use the handicap cheat after being unlocked. You do not have to win the Star Cup as this character.

Yoshi and Baby Mario court
Win the Mushroom Cup/Singles Tournament as Yoshi.

Mario Brothers court 2
Win all the Doubles Tournament Cups as Mario. Note: This is another Mario Brothers Court, but not the alternate way to get the previous one.

Super Mario and Wario Courts
Win the Mario mini-games for Mario and Wario in the Game Boy Color version of the game. Then, refresh data and send it to the Nintendo 64 through a Transfer Pak.

Wario Brothers court
Go through all the cups for Double Tournament with Wario.

Waluigi Court
Win the Medallion Match and set a new high score in challenge mode in the Game Boy Color version of the game. Then, refresh data and send it to the Nintendo 64 through a Transfer Pak.

Birdo/Yoshi court
Complete the Star Cup Doubles as Birdo to unlock the Birdo/Yoshi court.

Special Cups
Go through all the Tournament Cups with all the characters (including Shy Guy and Donkey Kong Jr.) to unlock the Special Cups, which are much harder than the previous one. Press [R] while selecting a character to access the Special Tournament in the menu.

The three Special Cups in order are Rainbow Cup, Moonlight Cup, and Planet Cup. Once you win a cup, you will move onto the next one.

See the same replay again
Press [B] while in a replay and you will see the replay again. This can be done at any point of the replay for as many times as desired.

Shining eyes during replay
If you are playing against Waluigi and he makes it past you, during the replay his eyes will shine for awhile.

Better chance of winning
When playing against the CPU, if you win a game or a set (in the final of the cup), save the game, then start again. In case you lose, you can continue the game and start with the advantage.

When playing against the CPU, press [B] then [A] for a slow shot close to the net, then run up to the net. After your opponent hits it, quickly hit the ball away from him. The ball will zoom by him, leaving him no time to react, and giving you an extra point.

When playing a two player tournament against the CPU, note that when one CPU player goes to one side the other goes to the opposite side, so as not to leave a single open space. Their main formation will look like this:

           X   
                        X
     -------------------------------

Try to get in the front row. Then, go in front of the opponent closest to the net. If the opponents happens to change rows, stay in front of the person closest to the net. Leave a little space between you and the net. Then, when the ball is headed toward you, save up as much power as possible then hit the ball over the opponent that is closest to the net, and right in front of you. If done correctly, the ball will go over one opponent's head and his or her partner will either be too far away to hit it in time or barely hit the ball.