When the original Star Trek television series started, male and female officers wore similar outfits. The male Star Trek uniforms consisted of black pants, black boots and a velour shirt with the symbol on the left side. Females wore the same type of shirt, with black boots and tights, and a black skirt, although in some cases they wore black pants. The color of shirt worn identified the branch the crew member belonged to. Those in green shirts worked for command personnel, while beige stood for operations, and blue was for medical personnel only. The velour shirts were changed to nylon shirts starting in the third season. You can find many of the Star Trek Costumes here.
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Star Trek: The Motion Picture
In Star Trek: The Motion Picture, the uniforms were changed. Officers wore jumpsuits, a tunic style shirt buttoned or tied around the waist and colored shirts and pants. Braids on the sides of the shirts indicated the rank of the officer. The main color used was gray and the dullness of the color on screen led to another renovation prior to the next film.
Star Trek II: The Wrath of Khan
In Star Trek II: The Wrath of Khan, uniforms were changed to a turtleneck shirt worn inside a jacket. Division was indicated by the color of the turtleneck, with rank shown by a pin on the shoulder. The skirt or pants worn with the outfit had a red stripe down the legs. They also wore a belt with the Starfleet emblem on the buckle and another emblem on their breast.
Star Trek: The Next Generation
In Star Trek: The Next Generation, members wore a jumpsuit. An insignia on the right collar indicated rank, and different colors were used on the stomach and sleeves to show branch. Going back to the original choices, red was for command, gold for security and engineering, and blue indicated a medical or science position. In the third season they changed from Spandex uniforms to uniforms made of wool.
Deep Space Nine
The Deep Space Nine version of the series used jumpsuits with an open neck. At times officers also wore a pale purple turtleneck under the jumpsuit. Other characters also wore the same uniform from the last series, with no indication as to why they did. Uniforms from both The Next Generation and Deep Space Nine were used by characters in Star Trek: Generations. The Voyager series used the same uniforms from Deep Space Nine.
Star Trek: First Contact
In Star Trek: First Contact, a turtleneck colored red, blue or gold underneath a black blazer. Bands on the shirt cuff indicated division, with pins on the collar showing rank. They also wore the emblem on their jacket and black pants along with black shoes. Enterprise uniforms featured a blue jumpsuit with colored accents. Members wore the patches on their right arm for the Starfleet and the left arm for the Enterprise.
The 2009 Start Trek movie brought more changes to the Star Trek uniform. All officers now wear a silver pin on their breasts and two shirts. The top shirt is gold, red or blue and covers a black tank top style shirt. Females in the movie wear black skirts and short sleeved shirts of the same color. The emblem of the Starfleet is still used, only now as a pattern on the top shirt worn by officers.
The first place to go for information relating to uniforms or anything else about the series is the official Star Trek page. They list a number of different guides and resources on all areas of Star Trek history. Users may also want to visit Star Trek Movie, which shows what the uniforms will look like in the next film.
All Experts offers help on the colors used in the uniforms on The Next Generation and the meanings behind those colors. There's also information to be found on fan club websites such as International Federation of Trekkers, Austrek and even the Star Trek entry at Fan History.
Other helpful websites with pictures include Spike's Star Trek Fan Page, Starfleet Uniform, Star Trek Movie Uniform Spoilers and Starfleet Uniforms from Wikipedia. The Wikipedia site is a great start tot the Star Trek Uniform Guide.