There are 36 Heart Pieces hidden across Hyrule in the Ocarina of Time remake, and every four of them adds a full heart to your life bar. Together with the eight Heart Containers from the dungeon bosses, they take you from three hearts to the maximum of twenty.
Most of the Heart Pieces sit where they always did, but the remake moved a few of them and changed some of the methods.
None are missable, and you can return to the child era at any time after finishing the Forest Temple by returning the sword to the Temple of Time.
Heart Piece #1: Lost Woods
Head into the Lost Woods from Kokiri Forest and take the first right. Then continue forwards past the target hanging on the tree to find two Skull Kids on the tree trunks. Take out the Ocarina while standing on the small trunk and repeat their notes for three rounds.
Heart Piece #2: Lost Woods
Enter the Lost Woods from Kokiri Forest and take the first left. Here, stand on the small trunk and play Saria's Song to the Skull Kid.
Heart Piece #3: Lon Lon Ranch
Enter the tower in the southwest corner of the ranch and move the boxes around inside to reveal a small tunnel you can crawl through. You will find the Heart Piece on the other side.
Heart Piece #4: Kakariko Village
Grab a Cucco and take it up the stairs to the windmill. Then walk past the door, jump and glide over the wooden fence. Here, climb the ladder on the right to find another Cucco at the top. Grab it and use it to glide to the blue roof, where you will find an NPC. Talk to him to get the Heart Piece.
Heart Piece #5: Graveyard
Talk to Dampé in Kakariko's Graveyard at night to start his Heart-Pounding Gravedigging Tour. Then walk up to any soft patch of dirt and pay him 10 Rupees to dig it up. If you are lucky, you will get the Heart Piece. Re-enter the graveyard for new spots.
Heart Piece #6: Graveyard
Pull back the grave at the far southern end of the row below the Royal Family's Tomb, then drop down the hole to find the Heart Piece in the chest.
Heart Piece #7: Hyrule Castle Town
After the Death Mountain gate opens, the lady by the Bombchu Shop says her dog is missing. During the night, find him round the back corner of the alley near the Treasure Chest Shop (there are other white dogs about). Interact with him and lead him back to the lady.
Heart Piece #8: Goron City
On the lower level of Goron City, you will see a giant pot with faces on it. First, light the torches around it with a Deku Stick so it spins, then drop a bomb (or bomb plant) in from above when the happy face is showing.
Heart Piece #9: Death Mountain Crater
Enter the crater from the very top of Death Mountain Trail. Then look right to see some mesh you can climb down. The Heart Piece is at the bottom. Just remember that after 4 seconds you will start taking damage, so be quick.
Heart Piece #10: Death Mountain Crater
Just like the previous one, enter the crater from the very top of Death Mountain Trail. Then head down the path to your left until you see some mesh on your left that you can climb down. Below it, you will find a Business Scrub who sells the Heart Piece for 100 Rupees.
Heart Piece #11: Hyrule Castle Town
After finishing Dodongo's Cavern, head to the Bombchu minigame building in Hyrule Castle Town. Then beat the three levels to get the Heart Piece.
Heart Piece #12: Zora River
This Heart Piece sits on the high platform above the singing frogs. Take the Cucco from behind the sealed gate by the Bean Seller, float to the big island's platform and climb the vines. Then fetch the second Cucco from the grotto on the island's south ledge and float down to the Heart Piece.
Heart Piece #13: Zora River
Carry the Cucco from near the Bean Seller up to the Zora's Domain waterfall entrance. From the high ledge there, float across the falls to the tiny platform with the Heart Piece.
Heart Piece #14: Zora's Domain
Use one of the lit torches next to King Zora to light a Deku Stick. Then turn around and head down the stairs, lighting the torch on your left. At the bottom of the stairs, light the next torch and head left towards the shop. At the shop, head left and down the stairs, lighting any unlit torches. At the bottom, head behind the waterfall on your right and light the final two torches to make a chest with the Heart Piece spawn.
Heart Piece #15: Lake Hylia
Head into the fishing pond building and pay the man 20 Rupees. Then head to the pond and look for a large fish. You will need to catch any fish over 50cm. Once you do, show it to the man at the counter to get the Heart Piece.
Heart Piece #16: Gerudo Valley
Grab the Cucco to the left of the bridge at the start of the area, then glide down to the other side of the canyon below to find the chest on a platform halfway down.
Heart Piece #17: Gerudo Valley
Grab the same Cucco you used for the previous Heart Piece, but this time land on the other side of the canyon at the very bottom. Then follow the path right to find the Heart Piece in a small room up the stairs at the end, behind the waterfall.
Heart Piece #18: Kakariko Village
Hookshot to the vines left of Impa's house instead, then climb up to the small roof.
Heart Piece #19: Graveyard
Head down the hole under the northwesternmost grave, race Dampé again and finish in under a minute.
Heart Piece #20: Kakariko Village
After Dampé's race (see the previous Heart Piece), continue forwards and you will come out on the upper level inside the windmill. Before dropping down, use the spinning platform in the middle to reach the Heart Piece on the right.
Heart Piece #21: Zora Fountain
Hop across the icebergs to the Heart Piece in the frozen lake.
Heart Piece #22: Zora Fountain
This one is at the bottom of the lake. Put on the Iron Boots to reach it.
Heart Piece #23: Lake Hylia Observatory
First, head to the fishing pond as Adult Link and catch a fish of 60cm or more. Then show it to the man at the counter to get the Golden Scale (which allows you to dive deeper).
Then head to the Observatory in Lake Hylia and complete the scientist's challenge by diving 9 m to the bottom of his pool.
Heart Piece #24: Gerudo Fortress
First, head to the Scarecrow at the entrance of Lake Hylia as Child Link. Talk to it, then bring out the Ocarina and make up a song with any 8 notes. After that, return to the Scarecrow as Adult Link, talk to it and play that same song back to it to learn the Scarecrow Song.
Now head to Gerudo Fortress as an adult. From the start, use your Hookshot to grapple up to the vine on your left (the same window as the cell, if they caught you before you rescued the 4 carpenters). From here, turn around and cross the rooftops on your left using the ladders until you go up a rubble ramp that is part of a destroyed building. At the top, play the Scarecrow Song to make a Scarecrow spawn on the other side of the gap. Hookshot to it to reach the other side, where the Heart Piece can be found.
Heart Piece #25: Gerudo Fortress
After rescuing the 4 carpenters in Gerudo Fortress, head to the large archery range to the southeast. Here, during the day, talk to the NPC while riding Epona to start the minigame. Score 700 or more points to get the Heart Piece.
Heart Piece #26: Hyrule Field
This is one of the new Heart Piece spots. First, as an adult, head to the small plot of land on the northern side of the lake to the right of the Hyrule Castle Town Drawbridge to find a symbol on the tree. Interact with it and it will tell you that the password is "Sell Somethin', will ya?".
Next, head to the same spot as a child and open up the grotto with a bomb. Then head inside and talk to the scrub. Tell him the correct password and he will sell you the Heart Piece for 100 Rupees.
Heart Piece #27: Hyrule Field
This is one of the new Heart Piece spots. The small chest behind the rock outcropping on the way to Gerudo Valley is locked if you find it as a child. Head there as an adult and read the fairy writing, then return as a child and it will open.
Heart Piece #28: Hyrule Castle Town
After getting the Lenses of Truth from Under the Well, head to the Treasure Chest Shop minigame in Hyrule Castle Town during the night. Play the minigame and "cheat" by wearing the Lenses of Truth. With them, you can always see which chest has the key inside. Always grab the key and get to the end of the minigame to get the Heart Piece.
Heart Piece #29: Graveyard
Plant a Magic Bean in the soft soil in the northwest corner of the graveyard as a child. Then return as an adult and ride the plant to the Heart Piece. You can buy the beans from the Bean Seller at the start of the Zora River area.
Heart Piece #30: Lake Hylia
Plant a bean in the soft soil outside the Observatory as a child. Then ride the plant as an adult up to the Heart Piece on the lab roof. You can buy the beans from the Bean Seller at the start of the Zora River area.
Heart Piece #31: Death Mountain Trail
Plant a bean in the soft soil just outside the Dodongo's Cavern entrance as a child, then ride the plant as an adult to the ledge above. You can buy the beans from the Bean Seller at the start of the Zora River area.
Heart Piece #32: Death Mountain Crater
Warp in as a child with the Bolero of Fire and plant a bean in the crater's soft soil close to the Fire Temple entrance. Then, as an adult, ride the plant to the top of the rock pillar. You can buy the beans from the Bean Seller at the start of the Zora River area.
Heart Piece #33: Evil Desert Colossus
After Sheik teaches you the Requiem to reach the Spirit Temple, warp back as a child and plant a bean in the soft soil to the left of the temple. Then, as an adult, ride the plant over the stone archway to the Heart Piece on top. You can buy the beans from the Bean Seller at the start of the Zora River area.
Heart Piece #34: Zora River
Play the Song of Storms for the frogs on the log.
Heart Piece #35: Zora River
Play all six non-warp songs for the frogs (Zelda's Lullaby, Epona's, Saria's, Sun's, Song of Time, Song of Storms), then win their fly-catching tune minigame by playing the correct notes as the butterfly hovers over the frogs. The correct tune is: L>Y>A>R>Y>A>R>L>R>L>R>A>Y>L.
Heart Piece #36: Kakariko Village
This is the reward for bringing 50 Gold Skulltulas to the Cursed Rich Man in the house in Kakariko Village.
