Yes, you can get your box braids wet. Ideally, you want to wash them at least once a week. Use a mixture of clarifying shampoo diluted with water and massaged into your scalp. Then rinse it out in the shower, letting the shampoo flow through to the ends. Use the same method with your conditioner. If you're taking a dip in the pool or ocean, just remember to rinse your hair with fresh water to prevent chemical or salt sediment building up.