Oh yeh, as far as casual goes - CC is casual everywhere. I don't know about the rest of Belize. But on the Island, you can go barefoot anywhere; a t-shirt or bathing suit top with shorts or a scarf wrapped around your waist is sufficient clothing. Don't bring fancy clothes, you won't need them and it's just more weight in your luggage. Bring very light-weight rain gear if you have it as 30 minute downpours do occur on occasion.