The underground harbor in Hogwarts’s Heritage is a small secret area under the castle, which has two chests, a chest with eyes and the page of the field leadership.
You can get to this area, floating from Calling or rising on an elevator near the Viaduct court.

• How to get into an underground Hall in Hogwarts Legacy
• How to go to the underground harbor from the yard of Viaduct

How to get into an underground Hall in Hogwarts Legacy

To get to the underground harbor swim, go to the Foo Flame boiling.
Start sail west to the castle.
In the end, you can see a waterfall when you approach the castle.
Directly to the left of the waterfall is the entrance to the cave with vines hanging above the entrance.

Swim and you will find yourself in the underground harbor.

How to go to the underground harbor from the yard of Viaduct

Find the elevator in the underground harbor a little faster than to swim.
Firstly, go to the Viaduct Yard FM Flame.
When you appear, go straight ahead, then hold on to the right side.
Continue to follow the wall to the right of you, and you will approach the door in the wall.

This is an elevator that will deliver you to the underground harbor.
The underground harbor is a small area, but if you want to find all the field pages in Hogwarts, you will need to visit it.
The chests there will also give you a little gold and a couple of objects.
To find out more about the Hogwarts’s Heritage, read the section How to enter the Treasury storage at the innkeeper’s barn in the Hogwarts Heritage here, in the game guidelines for professionals.