100 Days at Sea Crystal Skulls Guide – All Locations and Puzzles

The Shipwreck Region update in 100 Days at Sea adds five Crystal Skulls that are needed to unlock the Lich King boss. Each Crystal Skull is hidden on a different island, and you need to complete a unique puzzle before you can collect it. The islands are easy to recognize because they have a lighthouse producing a green light.

However, their locations are not fixed, and an island may not appear during every run. Once you find one, complete its puzzle, collect the Crystal Skull, and charge it at the pedestal to disable its lighthouse. After all five lighthouses have been turned off, the force field protecting the Lich King disappears.

How to Find the Crystal Skull Islands

There are five Crystal Skulls in total, with one hidden on each special Shipwreck Region island. Each island contains a green Shipwrecked Chest, but you cannot simply open it immediately. You must first complete the puzzle associated with that island.

Look for a lighthouse that emits a green light while sailing around the Shipwreck Region. This is the main sign that you have found one of the Crystal Skull islands. The five puzzles are:

• Raising the Flags
• Digging Mounds
• Extinguishing Lanterns
• Grave Symbols
• Ship Cannons

The islands spawn in different locations, so you will need to explore the sea during your run to find them.

1. Raising the Flags Puzzle

The first island has several lowered flags around its edges. They glow red, making them easier to notice. You will also see a green chest protected by a small force field. Follow these steps to complete the puzzle:

1. Sail around the Shipwreck Region until you find an island with a green lighthouse.
2. Look around the edges of the island for the lowered red flags.
3. Approach each flag and press E to raise it.
4. Skeleton enemies may appear after raising the flags, so defeat them if they spawn.
5. Place the Crystal Skull on the pedestal found on the island.
6. More enemies will appear around the pedestal.
7. Defeat the enemies to feed their souls into the Crystal Skull.
8. Continue fighting until the crystal is fully charged.
9. Once the enemies are defeated, the lighthouse will turn off.

Completing this puzzle allows you to progress toward disabling the force field protecting the Lich King.

2. Digging Mounds Puzzle

The second island uses a digging puzzle. You will find several dirt mounds scattered around the island, each marked with a red cross.

To complete this puzzle:

1. Find an island with a green lighthouse.
2. Search the island for dirt mounds marked with red crosses.
3. Approach a mound and press E to dig it.
4. Some mounds may spawn crabs, so defeat them when necessary.
5. Continue digging the different mounds until you find the green Shipwrecked Chest.
6. Open the chest to collect the Crystal Skull.
7. Place the Crystal Skull on the red pedestal in the middle of the island.
8. Defeat the enemies that appear.
9. Their souls will be used to charge the Crystal Skull.
10. Once the crystal is fully charged, the lighthouse will shut down.

You may need to check several mounds before finding the chest, so keep searching if your first few digs do not reveal it.

3. Extinguishing Lanterns Puzzle

This island is easier to recognize because it contains plenty of coconut trees and other vegetation. Once you land, look around the shipwrecked boats for green-glowing lanterns.

The goal is to turn off every lantern on the island.

1. Find the island with the green lighthouse and tropical vegetation.
2. Search the shipwrecked boats for green lanterns.
3. Walk up to each lantern.
4. Press E to extinguish it.
5. Repeat this for every lantern on the island.
6. A cutscene will play after all the lanterns have been extinguished.
7. The cutscene reveals the location of the Shipwrecked Chest.
8. A green barrier blocking the chest will also be lifted.
9. Go to the revealed location and open the chest.
10. Collect the Crystal Skull.
11. Place the skull on the pedestal.
12. Defeat the enemies that spawn and use their souls to charge the crystal.
13. Once the crystal is completely charged, the lighthouse turns off.

Make sure you check inside the wrecked boats carefully, as the lanterns can be easy to miss while exploring the island.

4. Grave Symbol Puzzle

The fourth island has a different type of puzzle involving graves and geometric symbols. Each grave has a symbol, and you will need to use those symbols to open a nearby building.

Look for a building with a wooden door. The door has several geometric shapes painted on it.

Here is how to solve the puzzle:

1. Find the island with the green lighthouse.
2. Search the area for graves with symbols on them.
3. Remember the symbols shown on the graves.
4. Find the building with the wooden door and geometric shapes.
5. Interact with the shapes on the door.
6. Enter the symbols in the same pattern shown by the graves.
7. Once the puzzle is solved, the door will open.
8. Go inside and find the Shipwrecked Chest.
9. Open the chest to obtain the Crystal Skull.
10. Place the skull on the pedestal in the middle of the island.
11. Defeat every enemy that appears.
12. Continue fighting until the Crystal Skull is fully charged.

After the crystal finishes charging, the lighthouse will shut down like the other islands.

5. Ship Cannon Puzzle

The final Crystal Skull island features a cannon puzzle. You can identify this island by its large rock and three nearby coconut trees.

There will also be several ships in the surrounding water with red-and-white targets.

You need to use the cannons on the island to destroy these targets.

1. Find the island with the green lighthouse.
2. Look for the large rock surrounded by three coconut trees.
3. Find one of the cannons positioned on the island.
4. Aim the cannon at the ships carrying red-and-white targets.
5. Shoot and destroy all of the marked ships.
6. After all targets have been destroyed, the Shipwrecked Chest will appear near one of the ships.
7. Open the chest to collect the final Crystal Skull.
8. Bring the skull back to the red pedestal in the middle of the island.
9. Defeat every enemy that appears.
10. Continue fighting until the Crystal Skull is fully charged.
11. Once the crystal is completely charged, the lighthouse will turn off.

This completes the fifth Crystal Skull puzzle.

What Happens After Collecting All Five Crystal Skulls?

Once all five Crystal Skulls have been collected and their respective lighthouses have been powered down, the force field around the Shipwreck Region boss area will disappear.

• You will receive a notification telling you: “The forcefield is lifted, the Lich King awaits…”

This means you have successfully completed the Crystal Skull objective and can now challenge the Lich King. The Lich King is the major boss of the Shipwreck Region. Defeating him gives you the Necromancer Staff, making the Crystal Skull hunt an important part of progressing through the new area.

Finding all five Crystal Skulls in 100 Days at Sea requires exploration, but each puzzle follows a clear objective once you know what to look for. The main challenge is finding the correct islands because their locations are randomized and they may not appear in every run.

Keep an eye out for green lighthouses while sailing. Once you locate an island, identify its puzzle and complete it to access the green Shipwrecked Chest.

After all five Crystal Skulls have been charged and the lighthouses are disabled, the force field will disappear and the Lich King will become available. Defeat the boss afterward to claim the Necromancer Staff and continue your Shipwreck Region progression.