I know they’ve done a few.
In The Original Series, I can think of:
All Our Yesterdays
The City on the Edge of Forever
Tomorrow is Yesterday
Assignment: Earth
I know the TOS episodes cold; I don’t know any of the other series well enough to compile such a list.
But surely someone else does?
From TNG:
Time’s Arrow
All Good Things…
And of course, Star Trek: First Contact.
From DS9:
Past Tense
Visionary
I’m sure I missed some.
I don’t know Voyager or Enterprise at all, but I’m sure they’ve had their share.
Like TNG’s Tapestry, for example. :smack:
Trials and Tribble-ations
From the Animated Series:
Yesteryear
Time Trap
There was a LOT of time travel in Enterprise. Most of the first season, had to do with a Temporal Cold War, and Crewman Daniels was really a Starfleet officer from the…31st, century, IIRC. The Xindi were working for aliens from the future. Twilight, while not involving actual time travel, involved Archer becoming infested with brain parasites which exist in a different, reversed, time-stream, and destroying them in the future ends up preventing the infection in the first place, and thereby changing the past. The transition between seasons 2 and 3 - the episodes Zero Hour and Storm Front I and II - involved Archer transported back to WWII - a WWII that the allies were losing, thanks to alien intervention. In a Mirror Darkly, from near the end of the series, involved the Mirror Universe NX-1 finding the regular universe Defiant (from circa The Tholian Web).
There are two time-travel episodes I can think of in Voyager - A Year In Hell, IIRC, when an alien species attempts to wipe an enemy species from history, using a temporal weapon (the entire episode ends up removing itself from history in the end), and another episode where Kes was jumping through the timestream.
An obscure one from TOS: The Naked Time. At the end, they get out of their decaying orbit by mixing matter and anti-matter to make the chronometer run backwards for a few hours.
Which was originally intended to segue into Tomorrow Is Yesterday as a two-parter.
I’d love to know what it was with Star Trek and these decaying orbits. It’s not that freakin’ hard to put a lump of junk into an orbit that will last for many years, and I’d have thought you had to try extra hard to put the Enterprise into one that would flop into the atmosphere pretty much as soon as the power went off. :smack:
DS9 Trials and Tribble-ations
Voyager had quite a few.
An interesting one toward the end of the series was Shattered where different parts of the ship were in different time periods. At first Chakotay was the only one who could travel between them, but he innoculated the Captain. She had been in a part from before they went to the Delta quadrent so he had to explain the different time periods. It was a good retrospective.
and of course the series finale had a Janeway from the future trying to get the ship home faster so they could stop Tuvok from his brain wasting disease.
TNG : Yesterday’s Enterprise, Cause and Affect…