GameCube: Super Mario Sunshine Cheats

If you can restart the stage easily (and quickly), you should learn to quit when Mario is in danger of dying. This will let you have a large stock of lives to tackle stages and mini-stages that you want a lot of lives to spend on (the Dead Leaf in a Dirty Brook mini-stage comes immediately to mind).

Super Mario Sunshine Hint: Even Faster Lives
Go to Pianta Village and Choose the episode titled "Piantas in Need" and save all the Piantas and the villagers who gave you blue coins before will now give you 1-ups instead.

Super Mario Sunshine Hint: Yoshi spin jump
You can use Yoshi to jump much higher than the normal yoshi hover jump by rotating the analogue and pressing A, the spin jump can be executed as with Mario as well but you have the added bonus of being able to hover by holding A at the peak of the jump.

Super Mario Sunshine Hint: Running Nozzle Trick
When you get the running nozzle, (The one that dark Mario steals) then you can do a trick where you use it but do not run your water down. What you do is that you hold R to charge up. Once charged, you will run, but once you run, jump and let go of R. Then before you land, you quickly hold R again, but hold it about half way down. You will still be running, but you won't lose any water. Try it and see for yourself.

Super Mario Sunshine Hint: Neutralise The Second Law Of Motion
Mario loses life when he falls a long vertical distance. You can prevent this by pressing L to do a butt stomp to cancel his falling momentum. This trick will not work if the fall happens to be terminal or over a bottomless pit.

Super Mario Sunshine Glitch - Undertown
Unverified. I found this out on accident. To get below the town, at the beginning, when you appear in front of the statue, head North-West toward the Palm Tree (the one in front of the Pink-Roofed building). Climb to the top of it. Now, switch to the Hover Nozzel and hover toward the roof of the building. Stay low (about the side of the pink roof), as if you would grab on if you ran out of time or hit the side of the building. Keep your nozzel on as you hover into it.

If you did it correct, you will fall through the building, hear the underground music for a split second, then land under the town. If you plan to run around, jump constantly, because if you stay still for too long, you will die. And if you jump near the underground pipes, you will fall into them and you will no longer be under the town.

Super Mario Sunshine- Play as Yoshi! (Action Replay needed)
YOU NEED ACTION REPLAY, first off, put in the AR disc, find Mario sunshine and put in press down on the +pad to make mario smaller active. Find yoshi, hatch his egg, press down on the +pad on Yoshi, you won't see Mario but, you are now Yoshi!
undertown
go to the manta ray storm if you go to the fountain i was jumping and i fell underground but dont stop moving it might not work
high dive
if You press A an B mario will dive higher