Place beans in a large pot and cover with water. Bring to boiling, cover and turn off heat. Allow to soak overnight.
Coat slow cooker bowl with nonstick cooking spray. Drain beans and add to bowl. Add 4 cups water, onion, carrots, garlic, tomatoes, Italian seasoning and ham. Stir to combine, breaking up tomatoes with a wooden spoon.
Cover and cook on HIGH for 6 hours.
Season with salt and pepper; mash beans slightly to thicken soup. Serve with crusty bread and garnish with parsley, if desired.