1. Great Fairy Mask
Location: In the Great Fairy's Fountain in North Clock Town.
How to obtain it: After you've turned back into Link, find the fairy in Clock Town just as you did before. Take the fairy to the Great Fairy, and she'll give you the Great Fairy Mask.
Use: The Great Fairy Mask is extremely helpful for finding the stray fairies in the temples. If you want to find them all yourself, without the any help, wear the mask to find out if there is a stray fairy in the same room as you. If there is, the hair on the mask will shimmer. Also, while wearing the mask, if the stray fairies aren't trapped in bubbles, beehives, or treasure chests, they'll fly right to you.
Use it: In temples.
2. Bremen Mask
Location: Laundry Pool.
How to obtain it: Finish Guru-Guru's notebook entry.
Use: This mask gets animals to follow you while Link plays a marching tune on his ocarina.
Use it: Anywhere where there are small animals, but especially in the Cucco Shack at Romani Ranch.
3. Bunny Hood
Location: Cucco Shack at Romani Ranch.
How to obtain it: Finish Grog's notebook entry.
Use: The Bunny Hood makes you move faster and jump farther. It's a nice alternative to Epona, especially in areas where you can't take her.
Use it: Anywhere
4. Kamaro's Mask
Location: Mushroom rock in Termina Field.
How to obtain it: Finish Kamaro's notebook entry.
Use: Makes Link dance.
Use it: In West Clock Town in front of the Rosa Sisters.
5. Blast Mask
Location: North Clock Town.
How to obtain it: Finish the Old Lady from the Bomb Shop's notebook entry.
Use: Wear it and press B to blow things up. Use it sparingly, as it wastes health.
Use it: Whenever you have to blow something up, but don't have any bombs.
6. Mask of Truth
Location: Swamp Spider House.
How to obtain it: Find all 30 Gold Skulltulas in the Swamp Spider House.
Use: This mask, one of the only ones back from Ocarina of Time, does the same thing that it did in that game; lets you talk to Gossip Stones, and get different reactions out of people. A new use, however, is to read the minds of animals.
Use it: In front of Gossip Stones, people, or animals.
7. Mask of Scents
Location: Deku Cave.
How to obtain it: After Odolwa has been defeated, the Big Octo right of the Deku Palace (blocking the entrance to Deku Cave) will disappear. Enter the cave, and make it all the way to the end.
Use: Lets you "see smells".
Use it: If you want to make a potion for Kotake, use it to see where mushrooms are growing, and put their scent in a bottle.
8. Don Gero's Mask
Location: Mountain Village.
How to obtain it: Go inside the Goron Shrine and light all the torches. The chandelier will start spinning. Using the Goron Roll, break the parts of the chandelier until a slab of rock sirloin falls out. Take it to the freezing Goron in Mountain Village, near the small bridge (throw it to him). He will get down from where he was stuck, and reward you with the mask.
Use: It summons frogs to the Mountain Village after Goht has been defeated.
Use it: 1. In the Laundry Pool.
2. Near the entrance to the swamp.
3. In Woodfall Temple, defeat the Gekko.
4. In Great Bay Temple, defeat Wart.
9. Romani's Mask
Location: Termina Field.
How to obtain it: Complete Cremia's notebook entry.
Use: Lets you into the Milk Bar after 10:00p.m.
Use it: In East Clock Town.
10. Circus Leader's Mask
Location: Milk Bar.
How to obtain it: Complete Gorman's notebook entry.
Use: If you wear it while helping Cremia deliver Chateau Romani, the bandits won't attack you.
Use it: While you are helping Cremia deliver Chateau Romani.
11. Garo's Mask
Location: Gorman Track.
How to obtain it: Beat the Gormon Bros. at their horse race.
Use: Lets you enter Ikana Valley and fight Garos.
Use it: In Ikana Valley.
12. Stone Mask
Location: In circle of stones between Ikana Valley and Ikana Graveyard.
How to obtain it: Use the Lens of Truth to see a soldier inside the circle of stones. Talk to him, and give him either a Red Potion or a Blue Potion.
Use: Certain enemies and Gerudo pirates won't be able to see you.
Use it: Around certain enemies and in the Pirates' Fortress.
13. All-Night Mask
Location: Curiosity Shop on Day 3.
How to obtain it: Stop Sakon from robbing the old lady on Day 1 and the mask will appear at the Curiosity Shop on Day 3, but for the cost of 500 rupees.
Use: Keeps Link awake during Anju's grandmother's stories.
Use it: When talking to Anju's grandmother.
14. Keaton Mask
Location: Curiosity Shop's Back Room, Day 3.
How to obtain it: Go to the Curiosity Shop's Back Room (through the Laundry Pool) on Day 3 from 1:00p.m. - 10:00p.m. and talk to the shopkeeper.
Use: Summons the ghost of Keaton.
Use it: After clearing out a group of moving shrubs, the ghost of Keaton will appear if you wear this mask.
15. Kafei's Mask
Location: Drawing Room in the Mayor's Residence.
How to obtain it: Talk to Madame Aroma on Day 1 or 2 from 10:00a.m. - 8:00p.m.
Use: Townspeople will tell you about Kafei.
Use it: Anywhere in Clock Town, and during Anju's notebook sequence.
16. Postman's Hat
Location: Outside the Milk Bar, Day 3.
How to obtain it: After allowing the Postman to deliver the letter from Kafei to Madame Aroma, talk to him outside the Milk Bar.
Use: Lets you look in mailboxes.
Use it: In Clock Town.
17. Couple's Mask
Location: Stock Pot Inn Employees' Room.
How to obtain it: Finish Anju and Kafei's notebook sequences, and be in the Employees Room before the end of the world.
Use: Helps Mayor Dotour decide what to do about the carnival.
Use it: In front of Mayor Dotour.
18. Captain's Hat
Location: Ikana Graveyard.
How to obtain it: Beat Captain Keeta, and open the big treasure chest.
Use: Stalchildren talk to you and don't attack you.
Use it: In Ikana Graveyard and the Oceanside Spider House.
19. Gibdo's Mask
Location: Ikana Canyon's Music Box House.
How to obtain it: Play the Song of Healing to Pamela's father.
Use: Gibdos talk to you.
Use it: Beneath the Well and around Gibdos.
20. Giant's Mask
Location: Stone Tower Temple (upside-down).
How to obtain it: After defeating Eyegore, open the treasure chest that appears.
Use: Makes Link huge.
Use it: While fighting TwinMold.
21. Fierce Deity's Mask
Location: The Moon.
How to obtain it: Give all your masks (save the three transformation masks) to the children on the moon.
Use: Link turns into a huge and mighty warrior who's sword can fire magical beams.
Use it: In boss rooms.