Atlantica 100% Walkthrough Guide – Kingdom Hearts 1.5 Final Mix
Due to Donald’s transformation magic, the party has no trouble breathing underwater or swimming. When you first land you’ll meet Ariel and go through a bit of a movement and combat tutorial for your time in Atlantica. Ariel’s fish friend (Flounder) will swim off and you’ll need to find him a couple of times to prove you can navigate underwater, if you simply lock on to him and swim in his direction Sora will automatically raise or lower in the water as needed. Once that’s over you’ll trigger a fight with some new Heartless:
New Heartless: Sea Neon
| New Heartless | Sea Neon |
| HP: | 30 |
| EXP: | 8 |
| Drops: | Frost Gem (4%) Ether (1%) Blizzaga Ring (0.2%) |
Once you clear the Heartless you’ll need to hit the shell in the centre to tell the other characters that the Heartless are gone and its safe to come out. They’ll inform you that maybe the Heartless are after the Throne and that you should follow the Yellow Trident markers on the walls to reach it.
Switch in Ariel to your party if you want, just remember this means you wont be able to activate any Trinities you come across immediately. Make sure to double check her settings and abilities before moving on.
Undersea Valley
The first area we come to is called the Undersea Valley. The first small clam you should notice on your left can be hit to open and reveal an Elixir. Swim around a little to trigger all the enemie spawns, take a moment and defeat them all to make collecting some items easier. Near the base of the wall you should find a Red Clam, this can be opened with Fire Magic for a Mythril. Behind it and up higher is another regular clam, hit it to recieve a Mega-Ether. You’ll find another regular Clam on the sea floor, hit it for a Mega-Potion. If you look around the lower level of the area you’ll find another Clam hidden in an alcove containing a Mythril, with one final Clam near a vent that contains a Cottage. Once you’ve cleared the area follow the Yellow Trident into the Calm Depths.
Once you’re in the Calm Depths go to your right and the current should push you into the next hole in the wall down. In here you’ll find a bunch of Search Ghost enemies, defeat them and target the Red Sea Urchin high up on the left wall, hit it with Fire Magic twice to open a shortcut for later. Once you’re done, use the exit to reach the Undersea Cave.
Defeat the enemies and smack the Clam to claim a Cottage. Swim up to find the Yellow Trident pointing straight up. Follow it out through a hole and into the Undersea Gorge.
Undersea Gorge
Spend a minute and defeat the enemies, once you’re done, you’ll find a blue Clam towards the seafloor, use Blizzard Magic to open it for a Mythril Shard. You’ll also find a regular Clam around here too, this one contains a Mega-Ether. If you look at the far end of the Undersea Gorge you should see a large rock blocking something, head over to it, and enter Ariel’s Grotto.
Inside Ariel’s Grotto, you’ll find 3 chests. Since it’s full of stuff, all you want to do is use your lock on to target the chests and then swim to them. You’ll find a Mega-Potion, Cottage, and another Torn Page. Once you’re done, head back out into the Undersea Gorge and follow the Yellow Tridents to finally arrive at Triton’s Palace.
Here you’ll run into a new Heartless:
New Heartless: Screwdiver
| New Heartless | Screwdiver |
| HP: | 48 |
| EXP: | 15 |
| Drops: | Hi-Potion (12%) Thunder Gem (4%) Thundaga Ring (0.2%) |
Defeat all the enemies. You’ll then find 3 regular Clams along the seafloor containing, a Cottage, a Mega-Ether, and an Elixir. You’ll notice a fourth Yellow Clam that needs a Thunder Spell to open as well, this contains a Mythril Shard. Take the exit on the far side of the area now to enter Triton’s Throne for a couple of scenes.
Once thats over you’ll want to turn around and head straight back to Triton’s Throne, this time have a look for a large Clam at the base of the Throne, hit it to reveal a Save Point. Use it and then leave the Throneroom, back to the Undersea Gorge, when you’re ready.
As you re-enter the Undersea Gorge you’ll encounter another new Heartless:
New Heartless: Sheltering Zone
| New Heartless | Sheltering Zone |
| HP: | 90 |
| EXP: | 20 |
| Drops: | Frost Gem (8%) Ether (4%) Blizzaga Ring (1%) |
Sheltering Zones are a fairly unique Heartless. They will split when they die, into 3 Sea Neon Heartless, unless you can defeat them using a Magic Spell or with a Critical Hit.
Ariel’s Grotto
Defeat the enemies as they spawn and make you’re way back to the Undersea Gorge and eventually Areil’s Grotto.
Once you enter Ariel’s Grotto you’ll trigger a scene between Sora and Ariel. Leave the Grotto to trigger a scene with Ursula as well.
Now that we’re back out in the Undersea Gorge, you’ll need to keep an eye out for a Dolphin. He’ll be swimming around the area, but only if there are no heartless. Roam around and look for him, defeat any Heartless that spawn as well. Once you’ve found him, press the Triangle button (on Playstation) to grab on. You need to ride him here for him to move onto the next area. Hop off after you’ve done a loop.
In between the two Yellow Trident symbols you should see an opening. Head through into the Undersea Garden. In here you’ll find a clam containing a Mega-Potion. Exit after you grab it. We now need to start making our way to the Undersea Valley. If you opened the shortcut (Red Sea Urchin) you can use it now. Start by heading back into the Undersea Cave and out into the Calm Depths. Here you’ll have a hole in the wall or a Red Sea Urchin. Hit the Urchin with Fire Magic twice to make it explode and cause a hole in the wall. Head through the hole into the Undersea Valley.
Just like we did in the Gorge, you’ll need to ride the Dolphin here. He’s scared of Heartless so make sure you defeat any that spawn as you look for him. If he is not here, you either haven’t defeated some Heartless that spawned, or you forgot to ride him in the previous area. Once you find him, grab on and after a lap or so he’ll take you into the Calm Depths and drop you off outside the entrance to the Sunken Ship area. Head in.
Sunken Ship
Once you enter the Sunken Ship area, head straight to the seafloor, and to the left is our first chest, open it for a Mythril Shard. You’ll find another chest inside some debris near an anchor, this one containing an Elixir. Once you’ve gotten both of these swim to the deck of the ship to find a doorway leading inside of it. Swim through it.
Infront of you is a chest containing the Crystal Trident, as you approach you’ll trigger a scene with a Shark, dont worry about him for now. Grab the Crystal Trident, head behind the staircase and you’ll be able to access an area with a clam below the ship. Hit the clam to obtain a Mythril. On the way back out you’ll see another chest concealed by the barrels near the staircase, grab it for a Mythril Shard. With all of the chests opened you’re now free to head outside.
Outside the Ship you’ll trigger our next Mini-Boss, just like Sabor from Deep Jungle, he’ll attack sometimes when you return to this Sunken Ship area.
Boss Battle: Shark
| Boss: | Shark |
| HP: | 200 |
| EXP: | 100 |
| Rewards: | Hi-Potion (100%) Ether (80%) Mega Potion (30%) |
The Shark can hit quite hard, so make sure to keep your HP and Aero up at all times. As long as you keep that in mind, just lock on and beat him down. He’ll swim off once defeated and it’ll take a few seconds for the items to float down.
Once you’ve beaten the shark examine the seafloor for an exit to the Undersea Gorge. Head through the opening to find a Geothermal Vent in front of you, smack it to activate it. It will push a chest out of the seafloor above you. Swim up and out of the hole, open the chest for an Orichalcum, and then head for Ariel’s Grotto. Inside, approach the Blue Trident symbol on the wall in front of you to trigger a scene. Ariel will leave your party for a little while after this.
Exit the Grotto and start to make your way to Triton’s Palace. Simply follow the Yellow Trident Symbols on the walls again. You’ll also trigger a couple of story scenes along the way.
As you approach the Throneroom you’ll find a new enemy waiting for you.
New Heartless: Aquatank
| New Heartless | Aquatank |
| HP: | 120 |
| EXP: | 30 |
| Drops: | Thunder Gem (8%) Mega-Potion (4%) Thundaga Ring (1%) |
Aquatanks will release the 3 Screwdivers that are attached to them as the fight progresses. They also use large-scale thunder attacks that will hurt you and heal any Screwdivers in the area. Once you’re through with the fight head into the Triton’s Throneroom to see another story scene. You can use the clam in the Throneroom after the scenes are finished to save if you need.
You’ll now need to make your way back to the Sunken Ship area. It’s highly likely the Shark mini-boss will respawn so deal with him once you get there. In this area, you’ll find a large pillar-looking rock against one of the walls with what looks like a seahorse skeleton imprinted on it. Head over to it to trigger Sebastian the Crab suggesting to use a secret switch nearby. After he hits the switch the rock will move to reveal the entrance to the Den of Tides area.
Den Of Tides
Defeat the enemies and take the right-hand side path when you can, this leads to a save point in a clam and another clam containing a Mega-Ether. This next Boss Battle is very unique, take the time to stock Sora’s (and everyone else’s) item slots with Ether’s and Mega-Ethers, whatever MP restoring items you have really. Make one of the shortcut buttons the Fira spell to allow you to quickly cast it while in battle.
During this Boss Battle you need to hit the cauldron in the middle of the room with Fira, I would fire off two of the spells, and then change position so that you dont get pinned down by the enemies attacks. Ursula will power her cauldron with her own magic spells, if it is allowed to ‘charge’ with her spells you will all be hit with a large magical burst attack. Instead, as its charging you want to fire your own spells into it, Fira being the fastest and lowest cost to use, so that it instead charges with our magic and will burst, stunning Ursula and allowing you free reign to attack her for a time. Once she recovers the process starts over. Make liberal use of the MP items in your inventory for this fight.
Once your prepared head out, back into the Den of Tides area and towards the Tidal Abyss and into Ursula’s Lair for the Boss Battle.
Boss Battle: Ursula (First Battle)
| Boss: | Ursula |
| HP: | 450 |
| EXP: | 1000 |
| Rewards: | Mermaid Kick - Shared Ability |
Once you defeat Ursula you’ll gain the Mermaid Kick shared ability, this will let you swim up the powerful current in the Calm Depths without assistance. Equip it now. Leave Ursula’s Lair and then immediately re-enter to trigger the appearance of a Sea Urchin, hit it with magic to make it explode and drop a chest containing a Mythril. Head out of the Den of Tides and into the Sunken Ship area, from here you can gain access to the Calm Depths. Head in and use your new Mermaid Kick ability to swim your way to the entrance at the very end of the powerful current. Upon entering you’ll trigger the next Boss Battle, so make sure you make any changes you need now. Equipping some Thunder resistance can also prove very helpful in this fight.
Boss Battle: Ursula (Second Battle)
| Boss: | Ursula (Giant) |
| HP: | 900 |
| EXP: | 1500 |
| Rewards: | Thundara - Thunder Magic Upgrade Ansem's Report 3 |
Ursula has a few attacks you’ll need to know how to deal with, the first is a set of bubbles that she can blow at Sora, these are easiest to simply swim to the left or right to avoid. Your Mermaid Kick ability will come in handy for dodging most of these attacks. She has a vacuum-type attack where she will pull Sora towards her and attempt to bite him when close enough. Use Mermaid Kick to Swim away from her to avoid this attack.
Her biggest and most frustrating attack is a large Thunderstorm she will call down around herself. This one is quite irritating, as you need to get within melee range to damage her, and that is also the hitbox of this attack. She’ll announce this attack ahead of time by saying “This won’t be pretty!” that’s your cue to try and create some space between yourself and her.
If you are having difficulty with this fight, most of her biggest damage spells are all Thunder-based. By equipping multiple accessories that boost Thunder Resistance you should be able to greatly reduce the damage of her biggest spells.
After the battle is won, Triton will regain his Trident and after a few scene’s he’ll reveal that Atlantica’s Keyhole is located in Ariels Grotto. Head there to finally seal the Keyhole. As thanks for everything, Ariel will gift us the Crabclaw Keyblade. This keyblade strikes a great balance between Physical and Magic power. Once everyone has said their goodbyes, head to the nearest save point to board the Gummi Ship and head off on our next adventure in Halloween Town.
Head over to Halloween Town to continue the story.
Atlantica – Post Hollow Bastion
Disembark in the Throne Room and head outside. Here you’ll need to defeat all the Heartless that spawn before you’ll be able to access White Trinity (#7) beneath the large domed structure in the center of the area. Activate the Trinity for a chest containing Orichalcum.
Head back to the Throne Room and board the Gummi Ship for Halloween Town.
Head over to Halloween Town for our next White Trinity.
