- Not to be confused with The Dragon's Palace, a location from Plants vs. Zombies: Journey to the West.
East Sea Dragon Palace was the fifth world in Plants vs. Zombies Online and the final one not in Adventure Mode. It took place in the East Sea in an aquatic setting. This world was underwater and all land plants would die after a period of time unless an Oxygen Algae was planted. It was also unfinished for unknown reasons.
- Oxygen Algae
- Bubble Flower
- Electric Anemone
- Mine Fruit (Adventure Mode only)
- Sea Anemone (Adventure Mode only)
- Litchi (Adventure Mode only)
- Sea Starfruit (Adventure Mode only)
- It is currently the only world in Plants vs. Zombies Online that was not based on a time period, but a Chinese legend.
- According to the legend, each of the four dragon kings had a huge palace in their seas, which are the East Sea, West Sea, North Sea, and South Sea.
- It was similar to the aquatic world in Plants vs. Zombies: Journey to the West, which is also called the Dragon Palace, as they had similar plants, they were the only worlds to be entirely water-logged, and they were also based off the same location in Chinese mythology.
- When a land plant was drowning, the sound of zombie biting could be heard, despite the fact that there were no zombies involved.
- All the land plant's projectiles had their own animation of going through water in this world.