the hydra is in a underground cave near Poseidon's statue.
in the underground cavern near Poseidon's statue
You have to wait until the hydra tries to bite you. You have to jump on the head to knock it out. Once all of the heads are knocked out, you swim below and you will find the scale.
Go to Aphrodite's place and talk to the life guard. Dive into a hole near the statue and swim to a cave where you find the hydra. Jump on the hydra's heads to knock it out. After it has been knocked out, click on its body to get the hydra scale.
The Hydra is in his underwater lair. Swim out from the beach to the underwater maze, then go right, down, and left to find the Giant Pearl and the entrance to the Hydra cave.
The hydra is underwater in Posidons temple/house. Once you get inside the house there is a big "pool". You can go to the one area and there is an opening. The hydras at the end of a maze underwater.
you can find the star in a musem and when you find the star you can upen the gate to this type of beach that is were u find the hydra skin in that tottaly ganly cave the livegaurd benn talkin bout
The item from the Hydra is a scale, not a hair. The item from Cerberus is a whisker. Find the Hydra cave in the underwater maze in Poseidon's realm. (The giant pearl is right outside.). Knock out the Hydra's 5 heads one at a time by jumping up when he tries to hit you, and landing on the head. Get a scale when he is knocked out fully.
In a cave at the bottom left of Poseidon's water maze.
To complete Mythology Island on Poptropica, you need to follow the quest given by Zeus to find five legendary items. These items are the Thread of Ariadne, Ring from Minotaur, Hydra's Scale, Golden Apple, and the Mirror of Medusa. By locating and retrieving these objects from different parts of the island, you can return them to Zeus and successfully complete the island quest.
On the island
Big Nate island while scuba diving while trying to find the lobster trap. Cryptids Island while try to find Nessie in the loch in a sub. Mythology island in the sea when you search for the pearl, defeat the hydra , and to ask for Poseidon's help only to get his trident. This list might not be all of the island but these i guarantee you can go under water in.
Just stay along the top, along the right side, then along the bottom until you reach the Hydra cave. The Giant Pearl clam is just above the entrance.