Just go to eldrich zone on crystal isles and look for big bubbles that have some black clams/oysters inside of them, put your angler fish inside the bubble, harvest, and enjoy the best black pearls harvester in the entire game, super easy, rank up for people to see this.

If on island and the center, get a diplocaulus for black pearls. They do increase damage to trilobites and auto harvest them. They also auto harvest eurypterids

On the new map, Lost Island- there is a sunken ship in the very bottom left corner. I mean, tucked almost right in the corner, where the barriers meet. If you go inside the sunken ship, to the bottom of it, you will find clams full of only black pearls. The devs have a sense of humor, I'll give them that!

On Fjordur, the only way to obtain Black Pearls without going underwater is through, one, the Magmasaur den at the volcano in a cave inside the Fire Wyvern den, or two, from taming Gachas found in Asgard. Hope this helps anyone playing on the new map.

Since I haven't seen anyone recommend this, on the Island, go to the cavern of lost hope also known as Artifact of Cunning cave and kill tusos. Make sure to bring lots of scuba tanks and some good dinos, hope this helps anyone

"This is for only mobile players. Just tame a otter and turn on his/her victim item collection from the corner side of your device and give his/her agreesion to attack target and whistle it to follow you. Then go to small fishes and punch them and wait for some time. Keep warned that your otter's have to kill and hervest that not you. If the otter kill and hervst the fish then it will give you black Pearl. But it has only 35.78% chance to give you black Pearl.This is the tip to get black Pearl safely without any damage. Jay hind

Just become Jack Sparrow and summon Calypso

If you are on old mobile and you wanna craft tek structures or items that cost a fortune of these things to craft, then do the "violent dance of the amphibian" dungeon as it is one of the dungeons that is available in the dunegon menu permanently as long as you have internet since the devs gave up on this game so they gave us these dungeons

Once you enter the dungeon find and open the featured loot chest and hope you get 100x black pearls (you can save scum on singleplayer)

The dungeon boss is reletively easy too it's just the Beelzemorbus and with this specific dungeon you will also get 60 element instead of 20.

After you complete the dungeon it will cost 5 amber to enter so you can wait until 8 pm est for the entry cost to decrease to 0 amber again then grind it until you have enough black pearls

first tame an ichthy then go to rag about 75,23 more black pearls then you can carry on the sea floor and not to dangerous just keep an eye out for megs

If you're on the island search the beaches when its raining and use a chainsaw on trilobites