The Legend of Zelda: Ocarina of Time Unlockables

Heart Pieces
Every four heart pieces you collect will add one heart to your health gauge.
UnlockableHow to unlock
Lake Hylia Heart PieceYou need the Golden Scale for this. Go to the lab and dive in the water. You should be able to touch the bottom and when you talk to the professor he'll give you this.
Hyrule Field Heart PieceWhen facing Lon Lon Ranch's entrance go right and make your way to the lone tree before the river. Bomb or hammer by the tree to make a hole appear and driop down. Now either dive or use the iron boots to sink to the bottom of the water for this.
Lost Woods Heart PieceAs a kid. Entering from Kokiri Forest go left and jump onto the smmall stump. Play Saria's Song to get this.
Gerudo Valley Heart PieceGrab the nearby chicken and jump off the right side of the bridge with it to float down to a walkway far below. Follow this to the right and jump off to behind the waterfall. Climb the ladder to reach this.
Lon Lon Ranch Heart PieceAs a kid, make your way over to the tower at the far side. Go in and move the boxes around to access the hole in the wall. Crawl through to claim this.
Kakariko Village Heart PieceWhen you reach Death Mountain summit ask the owl for a ride back down. Go left (Link's right) and slowly walk off the edge onto the small platform. Enter the hole to get this. Note that it may be possible to fly over to this ledge from the unfinished building by using a cucco.
Zora's Fountain Heart PieceAs an adult swim to the middle of the fountain, and with the Zoras Tunic equipped, use the iron boots to sink to the bottom.
Hyrule Field Heart PieceGo to the fences just outside of Lake Hylia. Get right in the center of the four fences and then use the megaton hammer or bombs. Drop down the hole that appears. Defeat the business scrub there and then talk to him. He should give you a heart piece for 10 rupees.
Zora's RiverGrab the cucco early on and then take it all the way up to the waterfall. Go past the waterfall and turn left to see the heart piece. Use the cucco to float over to it.
Gerudo Fortress Heart PieceAfter freeing the carpenters and gaining the pass, ride Epona around to the rear area and play the horseback archery game. Score 1000 points or more for this.
Gerudo Valley Heart PieceGrab the cucco and jummp off the left side of the bridge. Aim for the small platform set into the far wall with the crate. Smash the crate for the heart piece.
Death Mountain Trail Heart PieceGo to the cliff overlooking the cavern. Throw the bomb that you used to blow up the entrance to the cave. Before a bomb grows back, face away from the cave and backflip over the fence. You'll take a little damage, but you can reach the heart piece.
Kakariko Village Heart PieceGo to the very top of the tower and look out straight ahead from the ladder. Z-Target ahead and side-jump off the left side. You'll land on the fence and will be able to climb on the roof of the house. Talk to the guy there and get the heart piece.
Kakariko Graveyard Heart PieceUp on a ledge in a box on the left side. Climb the fence and then jump to the edge of the ledge with the box, you should have been able to hang and climb to the place where the box is located. Alternatively a magic bean can be planted as a child to make a plant as an adult if you're struggling to make the jump.
Market Heart PieceWin the treasure chest game. At the very end will be a chest with the heart piece. Use the lens of truth.
Market Heart PieceAt night, retrieve the white dog that's around the place that gets crowded with people during the day. Go into the alley, into the door that is facing you. Talk to the lady, and she will give it to you.
Market Heart PiecePlay the Bombchu Mini-Game as a child, eventually a Heart Piece will be the prize.
Desert ColossusAs a child plant the beans in the soil by the temple entrance,then come back as an adult. Jump on the flying plant and stay there until you see the heart piece on the rock formation and jump there.
Zora's River 2At the base of Zora's River, grab the cucco. As you make your way up the river, just before the frogs in the water, on the left is an uphill slant, leading to a gap and another ledge. Jump with the cucco, and as you meet the ledge, let go, and you will grab the ledge. then jump across to the pillar to get the heart piece.
Zora's River 3About half way up Zora's River, there will be a log coming out of the water to the land. Get on it, and walk out to the lighter wood spot. Equip your ocarina to make some frogs appear. If you play the song of storms, they will get excited, and give you a heart piece.
Zora's River 4At the same spot as Zora's River 3, bring out the frogs. then, Play all 5 of the songs that you can earn as a child (non warp songs, minus the song of storms) and with each of the songs, a frog will grow. once they are all grown, they will play a game with you. Each different frog will jump when you play a note, and there is one frog for each note ( c◄,c▲,c▼,c►, and (A) ) the game includes bugs hovering over one frog at a time, and you much (quickly) press the button for each frog to eat the bug. however the game is not random, and has a set pattern. the pattern is [ (A), c◄, c►, c▼, c◄, c►, c▼, (A), c▼, (A), c▼, c►, c◄, (A) ] Once you beat the mini-game, you will be rewarded a heart piece.