Yes, it's year round. You can go to their website Texas State Parks, Mustang Island. They have primitive campsites and ones with electric, etc. The showers & bathrooms are usually very clean (at least when we've been there).
Yes, as Sandy added. Pretty sure the bathrooms and showers were just redone. They are really nice. The campground nothing special but you are right on the beach there...better book now though they always fill up.
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