Diving in Coral Island: How to Unlock the Merfolk Kingdom & All Sea Critters

Coral Island includes every feature you’d expect from a farming sim game while remembering its Indonesian roots with its novel diving mechanic. We know the basics of fishing, farming, and mining all too well, but what is this new activity all about?

You suit up in an adorable diving ensemble, team up with a cute robo-buddy, and dive into the underwater world to heal corals. The goal is simple: clear the trash so corals can breathe again. However, that doesn’t mean you must clear every piece of trash in the area. And, as you explore, you might stumble upon some precious forageables, encounter critters, and even uncover a hidden civilization. This guide covers everything you need to know about diving in Coral Island.

How Diving Works in Coral Island: Tips & Tricks

Diving is pretty similar to mining. If you’ve played other farming sims, you’ll notice that trash can be collected like rocks can be broken. Instead of a pickaxe, you’ll use the scythe to remove trash from the ocean floor.

The goal is not to clear the entire area, though I’m sure that would make everyone feel better. Still, losing track of the objective will deplete your entire stamina bar.

To progress through the underwater map, you must uncover solar orbs, tiny, golden devices hidden underneath the trash. This technology will power up a solar pillar that will heal coral sites when it finds the right place. So, to heal a coral site on Coral Island, follow these steps:

1. Clear trash near a contaminated (black) coral site until a tiny solar orb emerges.
2. Activate the solar orb to power up the pillar nearby.
3. Remove the trash marked with red to unblock the solar energy’s path.
4. Wait for a little cinematic, and the coral site will be healed.

Every now and then, a sea turtle or seal will be freed from a root prison when the solar pillar is activated. Interact with them to receive a stamina-replenishing snack.

How to Use Kelp in Coral Island

While diving in Coral Island’s underwater map, you’ll start to amass quite the Kelp collection. In the early game, I would rush back home and drop all my kelp in the shipping bin, hoping to get a bit of gold.

Don’t be like me.

Use kelp to upgrade seeds, plants, and fruit trees in the lab. Kelp can be turned into Kelp Essence with the Extractor, a machine you can craft. With upgraded seeds, the quality of your produce will improve, and you’ll make way more money than just by selling regular kelp.

How to Unlock the Merfolk Kingdom & Enter Underwater Caves in Coral Island

As you progress through the underwater map, you’ll spot some caves with closed gates, like the Se Pulu and Dua Pulu caves. 

You’ll first need to unlock the Merfolk Kingdom to enter underwater caves. When you do, a character named Cho Oyu will give you access to the caves. 

Related: Romance in Coral Island: All Romance Candidates, Marriage & Children

I unlocked the Merfolk Kingdom in Coral Island by following the retreated root and opening the root-infested gate in Dua Pulu. This is all part of a main quest, so you should stick to the Heal the Ocean quest to get there.

How to Follow the Retreated Root & Find a Way to Open the Gate in Coral Island

After cleaning your first 20 coral sites, all of Se Pulu will be cleansed of the root. This will trigger a cutscene where you’ll meet some of the Merfolk. Though they’ll flee the scene, you can catch up with them by following the retreated root. However, this is easier said than done since the path is often blocked.

To follow the retreated root in Coral Island, I cleaned coral sites along the way. Usually, after cleaning one or two, the root barrier blocking the way would disappear.

Eventually, the root took over a gate, and the quest objective became quite vague: “Find a way to open the gate.” To open the gate to the Merfolk Kingdom in Coral Island, I healed all 20 Dua Pulu coral sites. This instantly caused the root to retreat further back, leaving the entrance to the Merfolk Kingdom open.

All Sea Critters in Coral Island & Where to Find Them

Appearance	Sea Critter Name	Season	Time	Location
	Arrow Crab	Spring and Winter	Evening and Night	10m
	Common Starfish	Any	Any	10m
	Tigertail Seahorse	Spring, Fall, and Winter	Evening and Night	10m
	Blue Lobster	Fall and Winter	Evening and Night	10m
	Mauve Stinger Jellyfish	Summer and Fall	Evening and Night	10m
	Cannonball Jellyfish	Spring, Summer, and Fall	Any	10m
	Upside-down Jellyfish	Any	Morning and Afternoon	10m
	Pom-pom Crab	Spring and Summer	Any	10m
	Sea Slug	Any	Any	10m
	Venus’s Flower Basket	Spring, Fall, and Winter	Any	10m
	Yeti Crab	Spring and Summer	Evening and Night	10m
	Flowerhat Jellyfish	Spring, Summer, and Winter	Evening and Night	20m
	Jayakar’s Seahorse	Spring and Fall	Any	20m
	Skunk Cleaner Shrimp	Any	Any	20m
	Eight-armed Sea Star	Any	Morning and Afternoon	20m
	Whelk	Spring	Any	20m
	Mantis Shrimp	Spring and Winter	Any	20m
	Hermit Crab	Any	Any	20m
	White-spotted Jellyfish	Fall and Winter	Evening and Night	20m
	Calico Lobster	Summer, Fall, and Winter	Evening and Night	20m
	Brisingida Starfish	Fall and Winter	Any	20m
	Ruby Seadragon	Summer, Winter	Morning and Afternoon	20m
	Giraffe Seahorse	Any	Any	40m
	Atolla Jellyfish	Spring, Summer, and Fall	Any	40m
	Cauliflower Jellyfish	Summer and Fall	Any	40m
	Horseshoe Crab	Spring and Summer	Evening and Night	40m
	Blue Crab	Spring, Summer, and Fall	Evening and Night	40m
	Sexy Shrimp	Any	Morning and Afternoon	40m
	Split-colored Lobster	Spring and Winter	Evening and Night	40m
	Crown-of-thorns Starfish	Spring, Summer, and Winter	Any	40m
	Hedgehog Seahorse	Any	Any	40m
	Chambered Nautilus	Spring	Morning and Afternoon	40m
	Fuchsia Flatworm	Summer, Fall, and Winter	Morning and Afternoon	40m
	Bloodbelly Comb Jellyfish	Any	Any	50m
	Pink Meanie Jellyfish	Winter	Any	50m
	Harlequin Shrimp	Summer and Winter	Evening and Night	50m
	Cotton Candy Lobster	Fall	Evening and Night	50m
	Sunflower Sea Star	Sea Star Summer	Any	50m
	Red Knob Starfish	Summer and Winter	Any	50m
	Blue Starfish	Spring, Summer, and Fall	Evening and Night	50m
	Leafy Seadragon	Fall	Morning and Afternoon	50m
	Shiho’s Seahorse	Fall and Winter	Any	50m
	Sea Anemone	Any	Any	50m
	Giant Isopod	Summer and Fall	Morning and Afternoon	50m
	Stone Crab	Spring, Fall, and Winter	Evening and Night	50m

All Ocean Scavengeables in Coral Island & Where to Find Them

Appearance	Ocean Scavengeable	Location
	Black Sea Urchin	10-20m
	Blood Clam	10-20m
	Duck Mussel	10-20m
	Giant Clam	10-20m
	Jackknife Clam	10-20m
	Mediterranean Scallop	10-20m
	Pacific Oyster	10-20m
	Steamer Clam	10-20m
	Zebra Mussel	20-30m
	Amber Pen Shell	20-30m
	Belon Oyster	20-30m
	Blue Mussel	20-30m
	Calico Scallop	20-30m
	Cherrystone Clam	20-30m
	Eastern Oyster	20-30m
	Gooseneck Barnacle	20-30m
	Purple Urchin	20-30m
	Quahog	20-30m
	Bay Scallop	40-50m
	Blue Oyster	40-50m
	Green-lipped Mussel	40-50m
	Green Sea Urchin	40-50m
	Kombu	40-50m
	Kumamoto Oyster	40-50m
	Patagonian Scallop	40-50m
	Razor Clam	40-50m
	Sea Lettuce	40-50m
	Geoduck	50-60m
	Heart Urchin	50-60m
	Horse Mussel	50-60m
	King Scallop	50-60m
	Olympia Oyster	50-60m
	Queen Scallop	50-60m
	Red Sea Urchin	50-60m
	Sea Grapes	50-60m
	Arame	Any
	Sea Mushroom	Any
	Sea Salt	Any
	Seaweed	Any