Sailor Mercury Costume
You need the following items for your Sailor Mercury Halloween costume:
Dress Like Sailor Mercury From Sailor Moon

Dress Like Sailor Mercury From Sailor Moon;
Sailor Mercury Sailor Outfit: Sailor Mercury's outfit consists of flared mini skirt, sleeveless shite shirt with big blue ribbons on breast, white gloves and gold headpiece.
Sailor Mercury Wig: She has short blue hair.
Sailor Mercury Boots: Sailor Mercury wears blue boots that matches her outfit perfectly.
Sailor Mercury Accessories: To complete your Sailor Mercury costume don't forget to get blue stud earrings and blue choker with star emblem on.
Sailor Mercury Halloween Costume

Ami Mizuno (水 野 亜 美) is one of the 5 original Inner Sailor Guardians of the solar system and was introduced as the 2nd Sailor Guardian. Your sailor's guardian identity is Sailor Mercury (セ ー ラ ー マ ー キ キ ュ ュ). Their powers are based on water and ice as well as on intelligence and computers.
Sailor Mercury Cosplay
As Sailor Mercury, she maintains her bourgeois appearance but wears a gold tiara on her forehead with a blue gem on the front. The dominant color of Sailor Mercury is blue as her Sailor Senshi shape comes in a variety of shades of blue. Her sailor's uniform is blue with two white stripes to match her blue skirt and knee-length boots. Both the front and back arches are light blue and have a blue brooch on the front arch. She wears blue stud earrings on both ears. Her knee-length boots are similar to both Sailor Moon and Sailor Pluto.