After cleansing the seas of pollutants with the fairy's help, Link can visit Jabu-Jabu's Belly.
Go to Jabu-Jabu
Jabu-Jabu is underwater, to the west of the Zora Village throne room in the present. Swim over to Jabu-Jabu and he will open his mouth, allowing you to swim in. If he doesn't, talk to King Zora in the present to get permission.
Get the Compass
Go north from the entrance and kill all of the monsters in here to reveal a chest that contains the compass. Remember to equip your weapon to the A button to use it underwater.
Get a Key
Return to the entrance of the dungeon and go west. You can swim over the holes in the floor, so swim over the northeast hole and equip the switch hook to A to move the top-left stone diamond to be above the bottom-left statue, then move the bottom-middle stone statue to be below the top-left statue. A key will fall from the ceiling.
Get the Map
Go north one screen and swim onto the yellow tiles. Press B to rise to the upper floor.
Go west and open the chest on the left to find the Dungeon Map.
Lower the Water
Go north, swim north across the water while avoiding the fireballs from the torches, and exit north.
Go one more screen north past the Like Like and Iron Masks.
Be careful of Pincers that pop out from the water holes and attack you. Go to the northeast corner of the room and push the lower block right and the upper block up. Exit to the east.
The red objects are spinning blade traps. They will start moving toward you when you walk into their path. Avoid them and go to the right. Use your key on the key block below the stairs. Go up.
Exit to the south. Get past the Iron Masks and Like Like, then go around and use the northwest exit.
Get past the Moldorm and exit to the north.
Press the red button to lower the water level.
Get a Ring
Go back to the stairs and go down. Go south one screen to a screen where a Spark is spinning around the center. Drop down the hole on the right side of the room.
Use the Switch Hook on the pot in the center of the room, then use it on a pot on the left side of the room. Open the chest up above to get a ring.
Get a Second Key
Exit to the south of the room where you got the ring mentioned above. Push the bottommost block to the right and go up and open the chest to get a key.
Raise the Water
Go south from where you just got the key, then east, then north. You will end up in the room two screens north of the dungeon entrance. Use the cane of somaria to put a block onto the switch. Go through the door that opens on the right.
Swim around to the stairs and go up onto the ledge. Go to the left and go up the stairs here.
Go north, then head east through the winding path. Use the northeast exit.
Go up the stairs to the platform on the right, then get rid of the pot and use the switch hook to get to the platform on the left. Exit to the west.
Use the switch hook on the diamond above you, then on the one on the left, then on the one below you, then on the one on the right. Go up the stairs.
Exit north and then go through the locked door on the left.
Step on the switch to raise the water level.
Get a Third Key
Go east, then south, then down the stairs. Use the switch hook on the stone diamond on the right, then exit east.
Go up onto the platform and then hop off to the right. Exit to the south.
Go through the winding path and exit to the south. Swim into the room to the east. Kill the Moldorms to make a chest appear that contains a key.
Get a Gasha SeedExit to the west, then swim to the top-left corner of the room and exit to the north, then exit west. Dive into the deep water. Go around and open the chest to get a Gasha Seed.
Go down the stairs here, then swim around to the room on the right. You will fight Angler Fish. You have to hit the light on its head to hurt it. Hit it with scent seeds to deflate it, then go over to the deflated fish and hit the light with your sword.
Get the Long Switch
After Angler Fish dies, go up the ladder that appears on the right.
If you don't have a key for the key block, use the switch hook on the stone diamond to the south. Exit south, then west, then north. Hop down to the lower level and go to the yellow tiles on the right. Go to the surface by pressing B. Then go east, then south, then swim to the east exit. Kill the Moldorms to get the key. Then go west, north, west, and dive into the deep water, then swim down the stairs and follow the path east to the ladder that appeared after you killed the Angler Fish. Go up.
Unlock the key block and open the chest to get the Long Switch. This is the same as the switch hook but longer. Use it on the diamond to the south. Then go down the stairs to the right, and exit to the west.
Get a Fourth Key
Use the long switch to get rid of the stone diamond on the left. Exit west. Then exit north and go down the stairs.
Follow the path until you get to a gap with a pot on the other side. Use the long switch on it. Continue along the path until you are back in a dungeon room. Kill the Barinade and Rope in this room. Use the long switch on the flower to get rid of it. You will get a small key.
Lower the Water
Exit to the south, then go onto the yellow tiles and press B to rise to the surface. Go north twice, then push the lower block to the right and the upper block up, and exit to the east. Avoid the spinning blade traps and go up the stairs.
Follow the path around and step on the red switch.
Get a Fifth Key
Go back around the path and go down the stairs. Go south, west, south, then stand on the blue tile, face south, and use the long switch to go to the bottom of the room and exit south. Go east, then jump into the hole. If you fall in the room where you were supposed to use the long switch, just exit east, push the block out of the way, then go south.
Use the long switch from the left to get the diamond out of the bottom area, then use the long switch on the pot up above to get yourself out of the bottom area. Move the diamond onto one of the switches, then use the cane of somaria to put a block onto the other switch. Open the chest to get a key.
Raise the Water
Go east, then north. Use the cane of somaria to put a block onto the switch and open the door to the east. Go through.
Swim around to the stairs and go left to the stairs to the upper level. Go north, then around the winding path to go north again, then get onto the platform and get rid of the pot, then use the long switch to go across to the other platform. Exit west.
Use the long switch to reach the stairs in the middle. Go up.
Go north, then west, then step on the switch to raise the water.
Get a Sixth Key
Go east, then south twice. Climb the stairs and use the long switch to go left, then use it to go down, then walk over and open the chest to get a key.
Get a Seventh Key
Jump down the ledge and go north twice. In the room with the many stone diamonds on the right side, make sure that the hole is full of water. If not, exit west and step on the blue switch, then go back east.
Use the long switch on one of the stone diamonds to go to the right side. Exit north, then go left and unlock the key block to exit west, then south. Don't step on any switches. Push the lower left block down and DON'T step on the red switch. Remember: the floor below you needs to be full of water. To make that happen, you have to have stepped on the blue switch on the right side of this room. If you are sure that you have done this, exit to the south.
Go around the path and go down the stairs to the second floor. Go south, west, south, and west again into a room with a chest. Use the long switch to reach it. It contains a small key.
Get a Gasha Seed
Go east, then south, then east. Go onto the platform at the top right and use the long switch to go to the bottom platform. Go east twice, then north twice. Go through the winding path and go north, then use the long switch to get over to the platform on the left. Exit west. Use the long switch to reach the stairs in the middle. Go up.
Go north, use the long switch to reach the upper right and exit north, then go west two times. Then go past the Moldorm and Iron Masks to reach the locked door at the upper right. Unlock it and go through.
Open the chest to get a Gasha Seed.
Get the Boss Key
Go east through two locked doors. Get the Boss Key from the chest.
Raise the Water
Use the long switch on the stone diamond and exit west. In the room with many stone diamonds, if there is no water in the hole, exit west and step on the switch, then go east again.
Reach the Dungeon Boss
From the room with many stone diamonds, make sure there is water in the hole (exit west and step on the switch if not), then go south, then down the stairs. Use the long switch to go to the right side of the room and exit east.
Hop down the ledge to the right and exit south. Go around the winding path and exit west.
Dive down into the hole, then swim west onto the blue blocks and press B to go up a level. Use the seed shooter if you want to activate the owl. Go south onto the ledge, then follow it around to the boss door.
Plasmarine swims toward you, so swim away. Sometimes it shoots an energy ball at you. Use the long switch on Plasmarine to make it change color. It is vulnerable to energy balls of the opposite color, so if it shoots a red energy ball at you, use the long switch on it to turn it blue and put it into the path of the red energy ball. It will get hurt. Do the same for the opposite colors. Be careful, because sometimes Plasmarine becomes electrified instead of shooting an energy ball.
Get the Essence
Get the heart container, then go west to get the essence, the Rolling Sea.
Afterward, you learn that the Black Tower has been completed. The possessed Queen Ambi receives powers of darkness atop the tower, causing people and animals to turn to stone again. The Maku Tree is unable to hear the final essence, but she knows that it is in Labrynna.
Go south from Jabu-Jabu. As you go south, a Zora will give you a Zora Scale. You can use the Zora Scale to enter the Sea of Storms.