There area a number of secret passwords and hidden coordinates that you can enter into the “NavMap” aboard the Airship in order to reach secret destinations. Some of these secret unreachable areas you may have noticed already during your travels if you saw them on your minimap.
You can actually discover these passwords by exploring within Final Fantasy X and seeking out all of the 1,000 year old ruins scattered across Spira (as mentioned by the game). You need to be able to read Al Bhed in order to decipher the ruins by seeking out each of the Al Bhed Primers.
This strategy guide is going to skip over those parts of the game though because you can access these areas without decoding the passwords on your own.
Talk to Cid on the bridge of the Airship to bring up the destination list. Select the “Input” option in order to enter the passwords. The three Al Bhed Passwords are:
Entering those passwords will allow you to enter the areas listed below.
Selecting the Mushroom Rock destination will put you on a secret path that leads to a treasure chest. The treasure chest can only be opened if you have already obtained the Celestial Mirror.
Selecting the Besaid Ruins 1 destination will lead you to a treasure chest that contains Victorious, which is a mediocre piece of armor for Rikku.
Selecting the Besaid Ruins 2 destination will lead you on a path to a treasure chest that contains Murasame, a mediocre weapon for Auron.
The only way to discover these locations without using a guide is to randomly guess and search different coordinates until you find them. Here are the coordinates of each of the unlockable locations:
There are a number of things to complete that involve venturing to Baaj Temple. Check out the Baaj Temple side quest section for additional information:
There are a number of side quests that can be completed by venturing to the Omega Ruins, just like at Baaj Temple. Check out the Baaj Temple side quest section for additional information: