Starfleet uniform (mid 2270s)
In the mid-2270s, a new Starfleet uniform design was introduced over the previous design, with many different variations. Most were gray, white, brown, or beige, and came either in a one-piece jumpsuit or with matching trousers and tops.

These uniforms bore rank insignia on the sleeve or on shoulder tabs. The delta shield emblem was adopted as the Starfleet insignia and was worn on the chest by shipboard personnel and flag officers. Base personnel, like those on Epsilon IX, continued to wear duty badges unique to their assigned base. ()

Distinctive features of this period included a life support monitor belt buckle and shoes attached to the trousers. This style of uniform was phased out by 2278. (; )

Standard duty uniform 
The standard Starfleet uniform was a two-piece tunic that came in a blue-grey, beige, brown, or white color, including any combination thereof. The tunic was worn untucked, and had a life support monitor belt buckle, though no visible belt. Rank insignia was worn as sleeve stripes, and an assignment patch showing a division color was attached to the tunic chest.

This tunic came with three variations of collars. The standard was a low flat collar, but there was also a V-necked flared collar version. The standard version could also be worn with a higher, more formal collar. A variant did feature a visible belt. ()

Short sleeved tunic 

A short sleeved version of the standard tunic was also available. This tunic featured either a low V-neck collar, or flared V-neck. Rank was shown by division color epaulets, and a division color assignment patch was attached to the tunic chest. The V-neck tunics were available in same colors as the standard uniform.

Admiral's uniform 

The flag officer uniform was a two-piece tunic with dark gray pants and a white and dark gray flared shirt with a high collar. Rank was shown by both epaulets and sleeve stripes, and a gold Starfleet Command pin was worn on the chest.

Rear Admiral James T. Kirk wore this type of uniform in his assignment at Starfleet Headquarters on Earth, when he was Chief of Starfleet Operations.

Wraparound tunic 

Crewmembers performing maintenance operations had the option of wearing a wraparound tunic. Its function is similar to the duty jumpsuits of the previous uniform style, and like those jumpsuits, it is worn with a black undershirt.

Station tunic 

An additional two-piece variant with a deeper, ribbed-V neck collar, wide-draping sleeves, and fabric belt, was commonly used by station personnel, such as on Epsilon IX station. Rank was displayed solely on shoulder epaulets.

Utility jumpsuits 
The duty jumpsuit was a one-piece uniform with integrated footwear, all one color. Rank was shown on the division color epaulets, and a division color assignment patch was attached to the chest. Some of these jumpsuits had large pockets located on the thigh.

A variant style included a raised collar, and zipped closure up the center. Another variant featured the zipped closure, and a wider, collarless neck-opening.

Engineering attire

Medical attire

Medical tunic 
For use in the medical department, a white tunic with a flared collar was used, with a medical green caduceus in place of the assignment patch.

Patient attire 

Patients in Starfleet sickbays wore a loose fitting white tunic with a hood like flared collar, the interior of which was orange. This was worn with white pants with prominent closers running all the way down to the ankle.

Away mission gear

Field jacket 

Landing parties had the option of wearing an tan protective jacket over their uniform, with pockets for supplies, displaying division and rank on the upper left sleeve.

Body armor 

Starship and base security personnel wore body armor, complete with helmets that bore the Starfleet delta.

EV suits 

 See: environmental suit and thruster pack

Embellishments

Assignment patches 
These uniforms indicated department by a colored circle behind the assignment patch, according to this code:

 White – Command
 Orange – Sciences
 Green – Medical
 Red – Engineering
 Pale Gold – Operations
 Gray – Security

Utility badge 

Certain utility jumpsuits featured a badge in place of the Starfleet insignia.

Rank insignia 
Rank was displayed on the standard uniform in similar golden sleeve braids on both cuffs as used on the previous uniform style, though ensign was now represented by a broken golden band (which had previously been used to indicate lieutenant junior grade.) Lieutenant was represented by a solid gold band, lieutenant commander by one solid and one broken gold band, commander by two gold bands, and captain by two solid gold bands with a broken gold band in the middle. 

Uniforms and jumpsuits that did not include sleeve braids could also display rank bands on shoulder epaulets. Flag officer uniforms were the only style to feature both. ()

Appendices

Background information 
The mid-2270s style uniforms were designed by Robert Fletcher, and most were only used in .

When William Ware Theiss, designer of  used on , was unavailable to work on Star Trek: The Motion Picture, Fletcher was selected to design uniforms better suited for the big screen, more believable, and less likely to be perceived as sexist given the changing styles of the 1970s. (The Making of Star Trek: The Motion Picture, p. 124) 

Fletcher developed an eighteen-page production document that laid out designs for divisions, ranks, and insignia, though not all suggestions were used in the film. 

Fletcher came up with the idea to connect the shoes to the uniform, to create a seamless "futuristic" look. The shoes were then designed by an acclaimed Italian shoemaker, and fitted for each principal actor (a "very difficult and expensive process.") On the first day on set, a mix-up had resulted in Majel Barrett Roddenberry's two-inch heels and Nichelle Nichols' five-inch heels being sewn to each others uniforms. (The Making of Star Trek: The Motion Picture, pp. 127-128) 

As  would later note: "when work started on , everyone was clear on one thing: they hated the Starfleet uniforms that had been designed for the first movie." Described as "bland", "formless and lacking in color," even Fletcher acknowledged he didn't like them himself. () George Takei stated that this version of the uniform was not comfortable, and that because of the way it was designed it required assistance to be removed – even for minor things such as using the restroom. He stated that the redesigned uniform featured in the rest of the films with the original series cast was brought about because of the cast's reluctance to film any further films with this version of the uniform. (Star Trek: Beyond the Final Frontier)

Elements of some uniforms were later recycled into the lab coats of the Regula I personnel in , while white and gray utility jumpsuits were dyed crimson and tan for use as the  junior crew/utility jumpsuits. ()

For more information, see: Star Trek II: The Wrath of Khan

Rank insignia 

In designing his Class A uniform, Fletcher began working on his concepts for rank insignia, which were identified by insignia placed on straps over both shoulders. Insignia were included for the ranks of "mid shipman", "lieut comm jr. grade", "lieutenant comm", "commander", "captain", "admiral" and "adm of the fleet". (Star Trek: Costumes, p. 45)

Jon Povill sent Fletcher a production memo, dated , explaining the rank insignia to be used in the film, with no reference to lieutenant junior grade or other flag officers. (The Making of Star Trek: The Motion Picture, p. 126)

Other than appearing in Fletcher's preliminary sketches as the insignia for a "lieut comm jr. grade", the otherwise unidentified triangular insignia was worn on the epaulets of several crewmembers. Several sold as part of the It's A Wrap! sale and auction listed them as representing the rank of petty officer.                

Crewmembers in the rec deck scene, including an operations crewmember (labeled James Doohan but played son Christopher Doohan,) wore an otherwise unidentified solid thin line-insignia.  Auctioned uniforms labeled for Walter Koenig and Nichelle Nichols also featured this insignia.   Several more unlabeled shoulder straps featuring the insignia were also included in the auction, which referenced  that it could indicate "crewman, second class."            

Shoulder straps with the rank insignia of lieutenant were also sold.

External links 
 
 
 
de:Sternenflottenuniform (2270er)
Starfleet uniform 06