The easiest way to do this is to simply run some water into your bathtub as though you were about to take a nice relaxing soak. If your home doesn’t have a bathtub, you could also use a large bucket or a plastic or rubber storage container, so long as it’s watertight.  Whatever container you end up using should provide enough room for you to stand in with both feet comfortably. Assuming you have neither a bathtub nor another suitable type of container at your disposal, you also have the option of searching for a natural body of water to go tramping through, or wetting your shoes thoroughly with a garden hose or faucet. The exact quantity you put in will depend on the amount of water you’re working with. Aim to use about 1 tablespoon of salt for every 1⁄4 gallon (0.95 L) of water in your container. This will give you a salinity of about 3.5%, which is roughly the same as the water in the ocean.  You can pick up a bag of purified sea salt at the supermarket for just a few dollars. Incorporating salt into your soaking water will simulate the conditions of wearing your Top-Siders in and around the sea, which is perfect if you’re going for an aesthetic that’s more veteran seaman than preppy yacht club. Slip into the shoes and pull as much slack out of the laces to make sure that they’re nice and snug on your feet. The tighter you make them now, the more they’ll loosen up once you get them wet. Don’t wear socks with your boat shoes (unless you enjoy the feeling of soggy feet). Canvas and textile shoes will begin sponging up water right away. It may take a few minutes for leather, which has natural water-resistant properties, to become fully saturated. As you stand in the container, rock forward onto your toes and backwards onto your heels to stretch the material through its full range of motion. Watch your step when climbing into your soaking container. Even though boat shoes are made for wet wear, accidents happen. Step out of the container carefully, allowing the water that’s collected inside the shoes to drain out as you do. Then, pat the upper part of the shoes all over with a clean, dry towel to wick up the remaining moisture on the surface. They don’t need to be bone dry—just dab them until they stop dripping.  It’s a good idea to put down an absorbent layer, such as a bath mat or second folded towel, to avoid covering the floor with standing water. Some Sperrys (particularly textile models that have been dyed to deep shades) aren’t as color-fast as others. If possible, select a dark-colored towel that won’t show signs of staining in case of bleeding. For best results, go for a short walk or do some simple exercises to introduce more movement to the damp material. Boat shoes are designed to dry quickly, so you shouldn’t have to wait long. In no time at all, your brand-new Top-Siders will soften up and take on an organic lived-in look, like you’ve owned them for ages.  If you’ve got other things to do, or just don’t particularly feel like wearing wet shoes, leave a wooden shoe tree in your Sperrys while they air out instead.  Leather expands when it gets wet and shrinks as it dries. Together, these two reactions will result in a unique fit that feels tailor-made for your feet.

Summary:
Fill a spacious container with about 6 inches (15 cm) of warm water. Add some sea salt if you want to give your shoes a more weathered look. Put on your Top-Siders and lace them up tight. Stand in the water with your shoes on until they’re wet all the way through. Towel-dry your Top-Siders to remove excess water. Wear your shoes around as they air dry to let them conform to your feet.