The Blue Hole Walkthrough – Assassin’s Creed Black Flag Resynced

TL;DR

• The Blue Hole is in the Charlotte region at coordinates 440, 145, west of Kingston
• There are 10 standard chests and 1 secret chest to collect
• The secret chest holds the Broadside Cannons Number Ultimate Plan — raises your cannon capacity to 18 per volley
• The secret chest is at the far north end of the dive, tucked under a broken overturned ship on the seabed
• This is a large, open-water dive with tons of space — sharks patrol here, so use the central wreck as cover
• Several chests are on the deep seabed below the large central ship — use wooden beams to push yourself down faster
• The secret chest isn’t inside an obvious structure — it sits on the sea floor in the northern corner

The Blue Hole walkthrough in Assassin’s Creed Black Flag Resynced covers one of the most open and spacious dives in the game. Unlike the cave tunnels of Devil’s Eye Cavern or the tight hull corridors of Antocha Wreck, The Blue Hole is a wide-open underwater environment built around a large central shipwreck and a deep, dark seabed below it. There are 10 standard chests spread across the site and a secret chest at the far north end containing the Broadside Cannons Number Ultimate Plan — one of the most impactful Jackdaw upgrades in the entire game. Here’s the full chest guide and everything you need to clear it in one clean dive.

The Blue Hole Location

The Blue Hole is found in the Charlotte region, west of Kingston, between Charlotte and Serranilla. The coordinates are 440, 145. Sail there and look for the Diving Bell marker on the surface — ship masts or the dive site icon depending on your map settings. Pull up alongside and interact with the prompt to lower your Diving Bell and drop in.

The Charlotte region is generally safer to approach than Chinchorro, but you’ll still encounter patrolling ships in the area. The dive site itself is easy to reach without major naval resistance.

How to Unlock The Blue Hole

Like all 7 underwater shipwrecks, The Blue Hole unlocks 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 every dive site on your map automatically.

If you’re new to diving, start with the San Ignacio Wreck walkthrough which covers the unlock in full. Once you’re set up, The Blue Hole is one of the best dives to hit early given how important the Broadside Cannons upgrade is for naval combat.

The Blue Hole Walkthrough – All Chest Locations

The dive area is significantly more open than other wrecks. There’s a large central shipwreck dominating the middle of the site, with chests spread across its decks, inside its hull sections, and on the deep seabed directly below it. The secret chest is at the far northern end of the entire dive area, away from the central ship.

Step 1 – Enter and Get Your Bearings

After the Diving Bell drops you in, take a moment to scan the area with L2/LT before swimming anywhere. The Blue Hole is large and open — much more than any other wreck — and white dot scanning helps you get a sense of where the chest clusters are before you commit to a direction.

A shark patrols this site. The large central shipwreck in the middle of the dive is your best cover option. When the shark approaches, duck behind or inside the hull sections to wait it out before continuing your sweep.

Step 2 – Clear the Central Ship Decks and Hull

The large central wreck is the core of the dive. Work through it systematically — there are chests on the upper decks accessible by swimming over the bowsprit and entering through deck doorways, chests in interior hallways on the lower decks, and chests tucked in alcoves between stairways. Use L2/LT constantly as you move through the ship.

There’s an air barrel on the central ship — use it once you’ve swept the upper sections before diving deep. You’ll need a full breath for the lower seabed chests and the run to the northern secret chest.

Step 3 – Dive to the Deep Seabed Below the Central Ship

Several chests are located on the seabed directly beneath the central shipwreck. The depth here is significant. Use the wooden beams and ship structure jutting out from the hull to push yourself downward faster — grab them as you swim past to get an extra burst of depth without burning extra breath.

Seaweed patches grow thickly along the seabed here. Use them for cover if the shark comes near while you’re looting the deep chests — swimming low through the seaweed makes it harder for the shark to spot you and gives you time to dodge if it does charge.

Step 4 – Swim to the Far North End (Secret Chest)

Once the central ship and seabed chests are cleared, top up your air at the barrel and head north to the far end of the dive area. This is the longest swim of the dive and feels further than you’d expect given how open the site is.

At the north end, look for a broken overturned ship section on the seabed — it’s partially collapsed and low to the ground. The secret chest is tucked underneath the hull of this overturned wreck at ground level. It’s not obviously visible from above, which is why many players miss it. Swim down and under the broken hull and open the chest to claim the Broadside Cannons Number Ultimate Plan.

One note from VGC is worth keeping in mind: this chest isn’t surrounded by an obvious full shipwreck — it’s just on the sea floor in a northern corner, beneath the overturned hull section. If you’ve reached the north wall of the dive area and can’t see a chest, scan with L2/LT and look lower, closer to the seabed.

The Blue Hole All Chests and Rewards

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

• Chest 1 – 1,000 Reales (central ship, upper deck)
• Chest 2 – 1,000 Reales (central ship, deck doorway)
• Chest 3 – 1,000 Reales (central ship, interior hallway)
• Chest 4 – 1,000 Reales (central ship, between stairways)
• Chest 5 – 1,000 Reales (central ship, lower section)
• Chest 6 – 1,000 Reales (seabed below central ship)
• Chest 7 – 1,000 Reales (seabed below central ship)
• Chest 8 – 1,000 Reales (seabed below central ship)
• Chest 9 – 1,000 Reales (northern area)
• Chest 10 – 1,000 Reales (northern area)
• Secret Chest – Broadside Cannons Number Ultimate Plan (far north, under overturned hull on seabed)

That’s around 10,000 Reales from standard chests plus the Broadside Cannons plan — one of the better single-dive payouts in the game. Combined with the plan’s impact on your Jackdaw’s firepower, this is one of the most valuable dives you can make. For more ways to stack resources, see our guide to farming metal and wood.

What Does the Broadside Cannons Number Ultimate Plan Do?

The Broadside Cannons Number Ultimate Plan unlocks the final broadside cannon upgrade for the Jackdaw, increasing your cannon capacity to 18 per volley. More cannons per volley means more damage output per broadside — and since broadsides are your main damage source in most naval fights, this directly multiplies the value of every Round Shot upgrade you’ve already bought.

To purchase the upgrade after getting the plan, you’ll need a Tier 3 Harbourmaster at Great Inagua, plus 20,000 Reales and 650 Metal. It’s one of the pricier upgrades, but it shortens every naval fight significantly — including against the Legendary Ships. See our Great Inagua upgrades guide for Harbourmaster progression, and our final ship upgrade locations and Ultimate Plans guide for the full set of plans.

Tips for Diving at The Blue Hole

• Use the central wreck as shark cover — This is the most open dive in the game, which means the shark has a lot of room to patrol. When it approaches, duck into the hull sections of the central ship and wait for it to pass before continuing your sweep.
• Use seaweed on the deep seabed — The thick seaweed patches near the bottom make good cover from the shark while you’re looting the deep chests. Swim low and use them to break line of sight.
• Use wooden beams to dive deeper faster — The seabed below the central ship is notably deep. Grab the wooden beams sticking out from the hull as you descend to boost yourself downward and save breath on the descent.
• Top up before heading north — The swim from the central ship to the far northern secret chest is longer than it looks. Use the air barrel on the central ship before making the run north so you arrive with a full breath.
• Look under the hull for the secret chest — The overturned ship at the north end has its chest hidden beneath the hull at seabed level. If you’re scanning from above and not seeing a white dot, swim lower and look under the broken structure.
• Scan constantly with L2/LT — The open layout means chests can be in any direction. Don’t assume you’ve cleared an area just because you swam through it once. The white dot scan will show anything within range you might have missed.

Seven Deadly Seas Trophy Progress

The Blue Hole 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 Devil’s Eye Cavern for the second-highest count of any dive site in the game, 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 The Blue Hole

With the Broadside Cannons Number Ultimate Plan secured, only one shipwreck plan remains — the Round Shot Strength Ultimate Plan at Kabah Ruins (738, 120) in the Navassa region. That’s the final dive site and has the highest chest count of any wreck in the game at 12 total. It’s also the plan you’ll want most before taking on the Legendary Ships.

Check our earlier shipwreck walkthroughs if you haven’t finished them: San Ignacio Wreck, Antocha Wreck, The Black Trench, La Concepción Wreck, and Devil’s Eye Cavern.

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 grabbed the game yet? It’s available on PlayStation Store, Xbox, Steam, and Epic Games Store.

More AC Black Flag Resynced Guides

• San Ignacio Wreck Walkthrough
• Antocha Wreck Walkthrough
• The Black Trench Walkthrough
• La Concepción Wreck Walkthrough
• Devil’s Eye Cavern Walkthrough
• All Underwater Shipwrecks Locations and Loot
• Great Inagua Upgrades Guide
• Crafting Guide
• All Treasure Map Locations
• Beginner’s Tips

Frequently Asked Questions