Barbie is wearing a blue stretch lacy ruched dress with an asymmetrical hemline. The dress slides on. And this can be worn as a skirt on taller dolls.
Barbie Clothes - Blue Lacy Ruched Dress or Skirt
Note that the dolls and stands are not included.
Clothes and shoes fit Barbie and other similar 29-30cm (11.5 inch) dolls like the Anko fashion dolls and Sparkle Girlz.