The core mechanic of the Swamp Palace is manipulating the water levels. Throughout the dungeon, you'll find various switches and mechanisms that either raise or lower the water. Some switches are activated by hitting them with your sword, while others might require a specific item like the Hookshot to reach. You'll often need to lower the water to access submerged pathways or raise it to float across gaps on platforms.
Careful planning is required, as changing the water level in one room might affect other connected areas. Sometimes, you'll need to merge into a wall to avoid being swept away by rising water or to reach a switch that's only accessible when the water is at a certain height. Keep an eye on the map to understand how different rooms are connected and how water flows between them. use your Zora's Flippers to swim through deeper sections and find hidden passages.