An excursion jacket (or field jacket) has been part of official Starfleet uniforms at various times in the organization's history, most notably in the 23rd century. Designed to be worn on away missions, the jacket provided officers with more protection from the elements than the standard uniform.
Excursion jackets in different styles were in use in the 2250s into the 2280s, but fell out of use sometime thereafter. (TOS: "The Cage", Starship Farragut "For Want of a Nail", Tamerlane, Star Trek: The Motion Picture, Star Trek II: The Wrath of Khan, Star Trek III: The Search for Spock)
- While not shown in televised episodes from the TOS era they appear in Starship Farragut (provided by Paul R. Sieber) and in Tamerlane.