Nico Robin is a tall, slender, yet athletic woman with shoulder-length black hair. In the manga, she is depicted with brown eyes, with dark, wide pupils. In the anime, she is depicted with blue, excluding the tenth and the twelfth movie, and she has a long, thin and defined nose. In the anime, Robin's skin tone is slightly darker unlike in manga colored artworks where it is lighter. Robin also resembles her mother greatly, with the exception of her hair color and style as well as having slightly darker skin tone than her. Robin's limbs are very long, especially her legs, contributing greatly to both her fighting capabilities (given the nature of her powers) and overall height.
She has no trademark looks like the others, though her all-purple cowgirl look from when she was first introduced is often associated as her trademark look. Like Nami, she seems to be fond of revealing outfits, and she is frequently wearing clothing that are either dark in color (often black or purple) or consists of leather (sometimes both). She is also fond of high heels, and they do not seem to affect the way she walks or her speed.
Robin sometimes wears a gold arm band with white strings attached to it with the letter N on it, which stands for her family name. She also had a similar one with BW on it, which stood for Baroque Works, but no longer wears it as she is no longer affiliated with the group. She has also worn a cowgirl hat on numerous occasions.
In the Alabasta Arc, she wore a skimpy cowgirl outfit consisting of a purple cleavage-exposing corset and matching miniskirt, both with white ornaments hanging from them, and a white fur-lined coat paired with a white cowboy hat and white high-heeled boots.
In the Skypiea Arc, she still wore her trademark white cowboy hat, along with a yellow sleeveless shirt and purple pants reaching to her calves, with a simple belt around her waist, and purple high-heeled Mary Janes. She sported her white ornament on her left arm.
In the Water 7 and Enies Lobby Arc, she wore a short, black, cleavage-revealing leather dress with long sleeves over what looked like a lighter, white polka-dotted under dress. She also wore black thigh high-heeled boots.
In the Post-Enies Lobby Arc, she was seen wearing a tight-fitting, pink t-shirt that has the Galley-La emblem at the front and a pair of black trousers. She also wore a pair of white high-heeled shoes. Later, she replaced the T-shirt with a tight, pinstriped purple buttoned sweater and dark high-heeled shoes.
In the Thriller Bark Arc, she wore a short purple dress with lace embroidered edges, stockings reaching up to her thighs held up by suspenders, and black high-heeled boots with two lines of buttons on the front.
In the Sabaody Archipelago Arc, she wore a black (purple in the anime) outfit consisting of a cowboy hat, a cleavage-revealing sleeveless shirt, with a wide, yellow collar covered with black concentric circle motifs, matching pants reaching down to her calves, and purple high-heeled Mary Janes. She also had a string of round and yellow ornaments that hung loosely from around her waist.
While imprisoned on Tequila Wolf, Robin wore a single-piece blue prison jumpsuit, which was left open to reveal her ample bosom. While on Tequila Wolf, Robin's skin tone seemed to lighten with color (possibly due to the cold weather of Tequila Wolf).
From the Return to Sabaody Arc near the end of the Fishman Island Arc, Robin's hair has grown longer, down to her lower back and is pulled back, revealing more of her forehead and ears. Her outfit after the timeskip now consists of a long pink sari-like skirt with a partially-zipped purple leather vest with a V-neck line similar to Boa Hancock's and a white rose printed on the left breast near the shoulder that exposed her stomach, sunglasses, pink high heeled pumps, and a pink backpack. She wears sunglasses which she hangs on her forehead and is seen wearing them during the battle with the New Fishman Pirates in the Gyoncorde Plaza.
Unlike the other members, Robin did not grow taller. She remains at 188 cm.
After the battle for Fishman Island, Robin wore a teal, long-sleeved V-neck dress. While exploring the Burning Lands of Punk Hazard during the Punk Hazard Arc with some of her crew mates, Robin removes her dress due to the heat to reveal a floral camisole and black shorts; she later ties the dress around her waist. She also has on very high heels with this outfit and still wears her new trademark sunglasses over her forehead. She later wears a long, spotted winter coat over this while on the Ice Lands of the island, which she took from a female member of Brownbeard'sCentaur Patrol Unit.
During the events in Dressrosa, she wears a very short, black dress. It is low cut, and hence, a large portion of her cleavage is visible. Her costume also includes her sunglasses, black high heel boots, and a white hat. She also chooses to wear her hair in a high ponytail.
After the events of Dressrosa Arc, she wears a light-colored tank top with word "Corrida" written on it along with dark-colored shorts (pink tank top and purple shorts in the anime).
During the Zou Arc, she wears a light purple turtleneck, dark fuschia colored shorts, and cream heels.
The author has also replied to a fan's question to saying that right now Robin's measurements are as follows:
Her height is 188 cm (6'2"), making her the third tallest member of the Straw Hat Pirates, after Brook and Franky.
Her 3 measurements are (according to Sanji and series creator Eiichiro Oda in supplemental material) B99-W59-H89 (38"-23"-36"), making her breasts an I-cup in Japan. After the timeskip, her measurements are B100-W60-H90, making her breasts a J-cup in Japan.