Devil’s Eye Cavern Walkthrough – Assassin’s Creed Black Flag Resynced

TL;DR

• Devil’s Eye Cavern is in the Cruz region at coordinates 453, 323, directly north of Charlotte
• There are 10 standard chests and 1 secret chest to collect
• The secret chest holds the Swivel Guns Ultimate Plan, which boosts gunwale damage by 150%
• This is the most unique dive in the game — it leads through underwater tunnels into a dry walkable cave
• Almost every standard chest here contains jewellery and valuables instead of flat Reales — making it the richest dive for total income
• No sharks — but jellyfish, sea urchins, and a fast water current with rocks are the hazards to watch
• After the secret chest, ride the current back — don’t try to swim back the way you came

The Devil’s Eye Cavern walkthrough in Assassin’s Creed Black Flag Resynced covers the most structurally different dive in the game. Instead of open ocean wrecks, this one funnels you through underwater cave tunnels and spits you out into a large dry cavern you can actually walk around in. With 10 standard chests loaded with jewellery and the Swivel Guns Ultimate Plan as the secret reward, this is also the most valuable dive for raw income. Here’s the full cavern route, every chest location, and how to navigate the tricky current section on the way back.

Devil’s Eye Cavern Location

Devil’s Eye Cavern is found in the Cruz region, directly north of Charlotte. The coordinates are 453, 323. Sail there and look for the underwater shipwreck marker — ship masts poking up from the water surface. Pull up alongside and interact with the prompt to deploy your Diving Bell and drop in.

Unlike the open-water wrecks like San Ignacio or Antocha, this site is built around an interconnected cave system. The layout twists more than any other dive in the game, so the step-by-step route below is worth following closely.

How to Unlock Devil’s Eye Cavern

Devil’s Eye Cavern unlocks alongside all other underwater shipwrecks after completing Diving for Medicines — the 22nd main story mission at the start of Sequence 6. That mission gives you the Diving Bell and marks all 7 dive sites on your map automatically.

If you’re new to diving, start with our San Ignacio Wreck walkthrough which covers the unlock mission. Once you’ve got the Diving Bell, Devil’s Eye Cavern is one of the best spots to hit early given how much the jewellery chests are worth when sold.

Devil’s Eye Cavern Walkthrough – Full Route

The layout here is nothing like a standard shipwreck dive. You’ll start near two sunken ships, push through a series of underwater tunnels, surface into a large open cavern you can walk through, find the secret chest, and then ride a fast water current back to the exit. Here’s the full route from start to finish.

Step 1 – The Two Entry Wrecks

After the Diving Bell drops you in, you’ll see two sunken ships directly ahead. There is one chest in each ship. Start with the ship on the right — swim through it quickly and grab the chest inside, dodging jellyfish as you go. Then swim down through the gap in the top of the ship on the left and grab the second chest.

Surface and use the air barrel nearby to fully top up your breath before entering the cave system. You’re about to go through a tunnel network, and this is the last easy air refill before it gets more complex.

Step 2 – Enter the Tunnel System

From the air barrel, you’ll spot an underwater cave entrance ahead in the rocky wall. Swim north into it and follow the tunnel. You’ll pass through a smaller room first — grab any chests as you go — then continue through the connecting passages. The tunnels twist but ultimately keep pushing you north. Follow them through.

There are no sharks in this dive at all. The hazards are jellyfish and sea urchins, which can both deal damage on contact. Neither can be fought — just navigate around them. Use the air pockets in the cave ceiling to top up breath whenever you spot one.

Step 3 – Collect the Underwater Tunnel Chests

Several chests are tucked through the tunnel sections before you reach the open cave. Keep L2/LT held to scan for white dots as you swim — the winding cave layout makes it easy to miss one tucked into a side alcove. Check your underwater map regularly to make sure you haven’t bypassed a chest room.

Most of these chests contain jewellery and valuables rather than flat Reales. Don’t be put off by the lack of a direct Reales number — the valuables sell for considerably more when you’re back on land. This cavern is the richest single dive in the game once you total up the sell value.

Step 4 – Surface Into the Dry Cave

Eventually the tunnel system opens upward and you’ll surface into a large, air-filled cavern — the actual Devil’s Eye. This is the only point in any of the 7 underwater shipwrecks where you can fully climb out of the water and walk around on dry ground. Take a moment here. Your breath fully refills the instant you surface.

There are additional chests here on the cave floor and on a raised ramp area. Climb the ramp and loot them before doing anything else. Once you have everything on this level, look to the left side of the cave for a tunnel entrance leading downward.

Step 5 – Find the Secret Chest (Swivel Guns Ultimate Plan)

The tunnel on the left side of the dry cave leads down into a lower dry alcove. Follow it to the end. The large secret chest is sitting right there — open it to claim the Swivel Guns Ultimate Plan.

This is a critical tip: do not dive back into the main water from the dry cave yet. If you do, you’ll have to swim the entire tunnel system from the beginning to get back here. Grab everything in the cave and both alcoves before going anywhere near the water exit.

Step 6 – Ride the Water Current Out

Once you’ve cleared every chest in the dry cave and grabbed the Swivel Guns plan, dive off the edge back into the water. This triggers a fast water current that carries Edward back through the cave system toward the exit. Don’t fight it — let it carry you.

The current section has rocks coming at you. Dodge them actively as you’re swept through — running into rocks repeatedly will damage Edward and can kill you if you’re not paying attention. It’s a fairly long sweep back, so stay alert until you’re flushed out at the other end.

Devil’s Eye Cavern All Chests and Rewards

Here’s the full breakdown of every chest and what you’ll find.

• Chest 1 – Jewellery / Valuables (right entry wreck)
• Chest 2 – Jewellery / Valuables (left entry wreck)
• Chest 3 – Jewellery / Valuables (tunnel section)
• Chest 4 – Jewellery / Valuables (tunnel section)
• Chest 5 – Jewellery / Valuables (tunnel section)
• Chest 6 – Jewellery / Valuables (tunnel section)
• Chest 7 – Jewellery / Valuables (dry cave floor)
• Chest 8 – Jewellery / Valuables (dry cave ramp area)
• Chest 9 – Jewellery / Valuables (dry cave)
• Chest 10 – Jewellery / Valuables (dry cave)
• Secret Chest – Swivel Guns Ultimate Plan (left alcove tunnel from dry cave)

Almost every standard chest here drops jewellery and valuables rather than flat Reales. When sold at a fence or trader, the total value of a full Devil’s Eye Cavern clear far exceeds the 1,000 Reales you’d get from a typical standard chest at other wrecks. This makes it one of the best early money runs in the game. For more ways to stack resources, see our guide to farming metal and wood.

What Does the Swivel Guns Ultimate Plan Do?

The Swivel Guns Ultimate Plan unlocks the final tier of your Jackdaw’s swivel gun upgrade, increasing gunwale damage by 150%. Swivel guns are your crew-targeting weapon — they fire at enemy sailors during boarding attempts and after you pull alongside a target ship. With this upgrade, they shred enemy crews dramatically faster, which means less fighting on deck and cheaper repair costs per engagement.

The upgrade is purchased at a Tier 3 Harbourmaster in Great Inagua once you have the plan. See our Great Inagua upgrades guide for what to build first and our final ship upgrade locations and Ultimate Plans guide for the full picture of every plan in the game.

Tips for Diving at Devil’s Eye Cavern

• Top up before entering the tunnel — Use the air barrel near the entry wrecks before you go into the cave system. Once you’re in the tunnels, air pockets are the only refill source until you reach the dry cave.
• Use air pockets in the cave ceiling — Look up as you swim through tunnel sections. Natural air pockets form in higher parts of the cave roof. Edward can poke his head up into them for a quick breath refill without needing a barrel.
• Scan constantly with L2/LT — The twisting tunnel layout makes it very easy to swim past a chest in a side alcove. Keep the scan active and check your map often.
• Don’t dive back into the water from the dry cave early — Grab every chest in the cave and both alcove areas before going near the water. Once you drop back in, the current takes you straight to the exit and you can’t return without swimming the full tunnel system again.
• Dodge the rocks on the return current — The water current that flushes you out is fast and throws rocks at you. It’s a long section — stay alert and keep dodging until you’re fully out.
• Sell your jewellery after diving — The valuables from the chests don’t automatically convert to Reales. Visit a fence or any trading post after the dive to sell everything you picked up and collect the full income.

Seven Deadly Seas Trophy Progress

Devil’s Eye Cavern contributes 10 standard chests and 1 secret chest — 11 total — toward the 68 needed for the Seven Deadly Seas trophy and achievement. At 11 chests, it ties with The Blue Hole for the second-highest chest count of any dive site, behind only Kabah Ruins. Visiting also counts as a discovered Location for the Cartographer trophy.

See our complete underwater shipwrecks locations and loot guide to track your progress across all 7 wrecks and all 68 chests.

What to Do After Devil’s Eye Cavern

With the Swivel Guns Ultimate Plan in hand and your pockets full of jewellery, the remaining wrecks worth hitting are The Blue Hole at 440, 145 in the Charlotte region for the Broadside Cannons Number Ultimate Plan, and Kabah Ruins at 738, 120 in the Navassa region for the Round Shot Strength Ultimate Plan. Both are excellent for boosting your Jackdaw’s offensive firepower before taking on the Legendary Ships.

Check our earlier shipwreck walkthroughs if you haven’t cleared them yet: San Ignacio Wreck, Antocha Wreck, The Black Trench, and La Concepción Wreck.

For more Jackdaw content, see our guides on how to beat all 6 Legendary Ships, the Legendary Ships mortar trick, and ship upgrade and customisation.

Haven’t got the game yet? Pick it up on PlayStation Store, Xbox, Steam, or Epic Games Store.

More AC Black Flag Resynced Guides

• San Ignacio Wreck Walkthrough
• Antocha Wreck Walkthrough
• The Black Trench Walkthrough
• La Concepción Wreck Walkthrough
• All Underwater Shipwrecks Locations and Loot
• Great Inagua Upgrades Guide
• Crafting Guide
• Kenway’s Fleet Guide
• All Naval Contracts Locations
• Beginner’s Tips

Frequently Asked Questions