To quickly hydrate a cat, there are a few steps you can take to help replenish their fluids. You can try enticing your cat to drink by adding a small amount of water to its wet food or offering them a low-sodium chicken broth or tuna juice in its water. Also, try putting ice cubes in its water, which it can lick. These solutions can help increase your cat’s intake fast.
Another effective method is to use a syringe or dropper to put water directly into your cat's mouth. Keep the water at room temperature, and gently administer small amounts at a time to prevent choking. Be patient and allow your cat to swallow before giving more water.