Return to most recently visited sanctum
At the load file screen, press and hold L(shoulder),Start,and Select before loading the file. When the file is loaded, Isaac and company will be inside the most recently visited sanctum.
Contributed By: Lasareth.
Unlock Battle Mode
To unlock battle mode, save after you leave the city of Vale. A new option will appear on the option menu.
Contributed By: FinalEnding260.
During the conversation following the clearing of Sol Sanctum, the Great Healer will ask for your decision as to whether you feel up to the burden of saving the world. Say 'No.' and he will warn you that you cannot take back your decision after leaving the village. Exit the building. Congratulations, you've completed Golden Sun, by destroying Weyard.
Contributed By: JetZefRadio.
When you travel through the Suhalla Desert, you'll come into contact with various monsters that can create tornados on screen. If you explore all of the desert, you'll eventually come across a giant pink tornado. However, don't use the Douse Psynergy to get rid of it. Instead, let the tornado pick you up and send you flying. You'll land on Crossbone Isle, a place that can't be found on the world map, and offers rare items and a tough boss.
Contributed By: discoinferno84.
Name All Party Members Plus Other NPCs
While Naming Robin/Isaac, press Select 3 times. You will hear a ting and then will be able to name Garet, Mia, and Ivan.
To name Felix, Jenna, and Sheba, press Up, Down, Up, Down, Left, Right, Left, Right, Up, Right, Down, Left, Up, and Select while naming Mia. You will hear another ting and will then be able to name those NPCs when you are through with Mia.
Contributed By: cronoebm.
After finishing the game once, at the title screen, hold the R button and Left on the D-pad, then press B. A new option will appear on the right called 'Send''. This allows you to transfer your clear data to a Golden Sun: The Lost Age cartridge by either a password, or by using a GBA link cable.
Contributed By: stncldrwg.
Unlimited Sol Sanctum Training
While in Sol Sanctum, you can usually encounter monsters until you reach level 5. Here is a way to go beyond that border. Make sure Jenna is at level 1. While in battle with a monster, let Jenna die. Do not revive her. Isaac and Garet can now train to any level you want.
Contributed By: King 0f Red Lions.