This Destiny 2 Sunken Isles Lost Sectors page will explain where to find all the mini-dungeons within that area of the EDZ / Earth Patrol space.
If you want more information on how to find Lost Sectors and the rewards they offer, our Lost Sectors locations page can help.
Destiny 2 Sunken Isles Lost Sectors
The three Lost Sectors in Sunken Isles are:
Skydock IV location
Location: Finding this Lost Sector in Sunken Isles can be really tricky, so instead of pointing you towards the symbol (which is already on your map), we're going to tell you how to find the entrance.
Head to the middle of the Cabal cruiser and drop down to either side. You should see an orange-lit road leading underneath it (see screenshot). From either direction, you should see a group of Cabal walking around on a raised platform.
Take these foes out (they're mainly Phalanx and Legionnaires, then head for the open doorway behind them. This is actually a shaft, so drop down, then turn left. Go through the doorway, then the second, then take another left. Welcome to Skydock IV.
Strategy: Go down the ramp, turn left twice more, then you'll encounter a Phalanx and a Legionnaire. Deal with them, then drop down the circular hole behind them to enter a larger corridor.
This area is filled with Psions (mainly on a raised platform to your left) and Legionnaires. Some Phalanx will also appear further down - focus your fire on the centre of their shields to take them out.
Head down this corridor and more Legionnaires and Psions will appear (joined by an Incendior and two War Beasts). Take out the War Beasts, then use the explosive canister on the back of the Incendior to take out the rest. Turn left, head down the corridor and turn left again.
You'll now be in the final area of this Lost Sector. This area is filled mainly with Psions and Legionnaires, as well as our boss, Devourer Darg.
He has those irritating heat seaking missiles that blind you, so hang back in the doorway and pepper him with fire. We found a well placed super took most of his health. The loot chest is at the far end of the room behind the big column.
For Season of Plunder, we have the Sails of the Shipstealer quest, Treasure Coordinates and Map Fragments, Cryptic Quatrains and weapons such as the Quicksilver Storm and Taipan 4FR. Meanwhile, there's the arrival of King's Fall and King's Fall challenges, plus weapons including Doom of Chelchis and Touch of Malice. For The Witch Queen, learn how to get Exotics including Dead Messenger and Parasite.
The Quarry location
Location: From the Sunken Isles spawn point, head towards the large hill besides the big Cabal cruiser. At the back of the cruiser, you'll find the symbol next to a small cave entrance.
Strategy: This dungeon has been overtaken by The Cabal, so you'll need to be prepared for Legionnaires, Gladiators, Incendiors, Psions and War Beasts. Enter the cave, turn right and head into the tunnel.
Turn left, drop down, go through the corridor, then turn right into a green-lit area. Go down here, make a right, then a left, and you'll enter a large area filled with Cabal.
Take out the Psions first - the Legionnaires will jump towards you, making them easy targets - while keeping an eye out for Indendiors in the distance. Push forwards and some War Beasts will be unleashed, take them out then head to the right-hand side of the room. Head into this tunnel, then turn right.
You'll now be in a yellow-lit chamber. Watch out for Psions and Legionnaires to your right on a raised platform, and a Gladiator that will rush you head on. Continue on, turn left, and crouch through a tunnel to enter the final area.
Take out the Psions on the ground, and those on a raise area to your left (where the loot chest will be). The boss, Fortifier Yann, is a Centurion, but he's quite slow and easy to flank.
Use a well placed super and some grenades to bring him down. Head up the ramp at the back of the room to collect your prize.