Add the rinsed split peas, diced ham, onion, carrots, celery, and garlic to the slow cooker.
Pour in the chicken broth, then stir in the thyme, bay leaves, salt, and pepper.
Cover and cook on low for 7 to 8 hours until the peas are soft and the vegetables are tender.
Remove the bay leaves and stir the soup to break up the peas slightly for a thicker consistency.
Taste and adjust salt and pepper if needed before serving.