There are a total of 22 Locked Treasure Chests in One Piece Odyssey, 8 in Waford, 4 in Alabasta, 5 in Water Seven, 1 in Marineford, and 4 in Dressrosa. To open these chests you need a special key which you will get when you complete all four side stories involving the "Zoners":

  1. Grand Line Quiz Kid Level 1 / 2 / 3 (Alabasta)
  2. Grand Line Quiz Lady Level 1 / 2 / 3 (Water Seven)
  3. Grand Line Quiz Madam Level 1 / 2 / 3 (Marineford)
  4. Grand Line Quiz Mister Level 1 / 2 / 3 (Dressrosa)

Once you open all 22 locked treasure chests, you will unlock the "Treasure Hunter" achievement / trophy.

Locations on Waford

1Sky Tower Locked Treasure Chest

Contains: Waford Necklace - A cube fragment containing extracted power of superior technology from Waford's days as a Sky Island (TP Efficiency +60%).

Sky Tower Locked Treasure Chest

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2Sky Tower Locked Treasure Chest

Contains: Odyssey Necklace - A cube fragment containing concentrated power extracted from the Straw Hats' adventurous spirit (GUTS +900).

Sky Tower Locked Treasure Chest

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3Waford South Locked Treasure Chest

To get here you must use three Zoro's Cube Fragments to upgrade his "Door Slice" field skill. Contains: Wild One's Necklace - A cube fragment containing concentrated power extracted from various wild monsters (GUTS +620).

Waford South Locked Treasure Chest

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4Waford South Locked Treasure Chest

Contains: Shock Element Jewelry - A cube fragment that adds lightning to your attacks. Only effective when the type added is a weakness.

Waford South Locked Treasure Chest

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5Waford South Locked Treasure Chest

Contains: Waford Ring - A cube fragment containing extracted power of superior technology from Waford's days as a Sky Island (HP Auto Regen +500).

Waford South Locked Treasure Chest

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6Waford South Locked Treasure Chest

Contains: TP Auto Regen Jewelry - Regenerates TP every turn (TP Auto Regen +70).

Waford South Locked Treasure Chest

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7Waford South Locked Treasure Chest

Contains: HP Auto Regen Jewelry - Heals HP every turn (HP Auto Regen +250).

Waford South Locked Treasure Chest

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8Waford South Locked Treasure Chest

Contains: HP Conversion Jewelry - A cube fragment containing special, extracted power. Heals HP based on damage dealt to enemies (HP Drain +10%).

Waford South Locked Treasure Chest

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Locations on Alabasta

9Desert Near Nanohana Locked Treasure Chest

Contains: Waford Crown - A cube fragment containing extracted power of superior technology from Waford's days as a Sky Island (HP Drain +20%). To get here Franky must be with you, because he can build the bridge.

Desert Near Nanohana Locked Treasure Chest

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10Great Sandy Desert Locked Treasure Chest

Contains: TP Regen Jewelry - Regenerates TP every time you receive damage (TP Regen + 50).

Great Sandy Desert Locked Treasure Chest

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11Great Sandy Desert Locked Treasure Chest

Contains: Evasion +20 Jewelry - Increases evasion rate (Lucky Evade +20%). To get here Franky must be with you, because he can build the bridge.

Great Sandy Desert Locked Treasure Chest

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12Nanohana Locked Treasure Chest

Contains: TP Cost Reduction Jewelry - Lowers the TP cost for skills (TP Efficiency +50%).

Nanohana Locked Treasure Chest

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Locations on Water Seven

13Dock One Locked Treasure Chest

Contains: Death's Edge Power Jewelry - Greatly increases ATK when on the verge of death (Adrenaline ATK +50%).

Dock One Locked Treasure Chest

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14Sewer Locked Treasure Chest

Contains: TP Regen Jewelry - Regenerates TP every time you receive damage (TP Regen +50).

Sewer Locked Treasure Chest

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15Sewer Locked Treasure Chest

Contains: Odyssey Crown - A cube fragment containing concentrated power extracted from the Straw Hats' adventurous spirit (HP +2500).

Sewer Locked Treasure Chest

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16Water Seven City Area Locked Treasure Chest

Contains: TP Auto Regen Jewelry - Regenerates TP every turn (TP Auto Regen +70).

Water Seven City Area Locked Treasure Chest

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17Water Seven City Area Locked Treasure Chest

Contains: HP Auto Regen Jewelry - Heals HP every turn (HP Auto Regen +250).

Water Seven City Area Locked Treasure Chest

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Locations on Dressrosa

18Dressrosa City Area Locked Treasure Chest

Contains: Fire Element Jewelry - A cube fragment that adds fire to your attacks. Only effective when the type added is a weakness.

Dressrosa City Area Locked Treasure Chest

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19Dressrosa City Area Locked Treasure Chest

Contains: Wild One's Crown - A cube fragment containing concentrated power extracted from various wild monsters (ATK +1400)

Dressrosa City Area Locked Treasure Chest

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20Dressrosa City Area Locked Treasure Chest

Contains: Freeze Element Jewelry - A cube fragment that adds freeze to your attacks. Only effective when the type added is a weakness.

Dressrosa City Area Locked Treasure Chest

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21New Royal Plateau: Bottom Locked Treasure Chest

Contains: Evasion +20 Jewelry - Increases evasion rate (Lucky Evade +20%).

New Royal Plateau: Bottom Locked Treasure Chest

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Locations on Marineford

22Marineford City Area Locked Treasure Chest

Contains: TP Auto Regen Jewelry - Regenerates TP every turn (TP Auto Regen +70).

Marineford City Area Locked Treasure Chest

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