This site is NOT a chronology - it is a viewing guide that will assist you through watching the entire franchise in in-universe story order, all the way from the 21st to the 43rd centuries, while making adjustments as needed to ensure an enjoyable viewing experience. It is not rigid - some episodes are shifted in the order to keep things as clear and fun as possible. The guide is updated regularly to stay current with new episodes.
Here’s that second Original Series pilot Lucille Ball fought for, now with (most) of the classic 1960’s Star Trek crew. Still no Dr. McCoy, Uhura, or Chekov, Kirk has a different middle initial, the uniforms and sets still aren’t quite right… but we are for the first time recognizably in the world of the show that started it all.
The Original Series - Season 1, episode 4 - Where No Man Has Gone Before
While exploring the energy barrier at galaxy's edge that crippled an earlier ship, Kirk's long-time friend and crewmate Gary Mitchell begins mutating into a god-like entity disdainful of the "mortals" around him.
Original airdate - September 22, 1966
Just to clarify - the original Star Trek will appear less advanced in terms of its designs and aesthetic compared to the other Star Trek shows we have watched so far, but this is only due to the limitations of television production at the time. This is not “true” in story terms - the technology and society in TOS should be read as on par with Discovery and Strange New Worlds, which all take place at roughly this point in the timeline, and the Enterprise, despite looking different, should be accepted as the exact same ship Pike commanded in Strange New Worlds.
As for the actual viewing order, to fully appreciate the development of the show, it's recommended to watch TOS in production order instead of by air date. In general, don’t get too hung up on continuity with the rest of the franchise in these early days - they take quite a while to pin some stuff down that the rest of the franchise takes for granted.
The Original Series - Season 1, episode 11 - The Corbomite Maneuver
While exploring an uncharted area of space, the Enterprise is outmatched and taken in tow by a massive spherical spaceship.
Original airdate - November 10, 1966
The Original Series - Season 1, episode 7 - Mudd’s Women
The Enterprise rescues con artist Harry Mudd and his "beautiful" female cargo.
Original airdate - October 13, 1966
The Original Series - Season 1, episode 6 - The Enemy Within
A transporter malfunction creates an evil Kirk.
Original airdate - October 6, 1966
The Original Series - Season 1, episode 2 - The Man Trap
A shape-shifting, salt-craving creature terrorizes the crew of the Enterprise.
Original airdate - September 8, 1966
The Original Series - Season 1, episode 5 - The Naked Time
The Enterprise crew catch a virus that removes their inhibitions.
Original airdate - September 29, 1966
The Original Series - Season 1, episode 3 - Charlie X
A powerful teenage boy wreaks havoc aboard the Enterprise.
Original airdate - September 15, 1966
In “Balance of Terror” we revisit the events of SNW’s season 1 finale, “A Quality of Mercy”, and see how differently events play out with Kirk in command of the Enterprise.
The Original Series - Season 1, episode 15 - Balance of Terror
After attacking an outpost, Romulans battle the Enterprise.
Original airdate - December 15, 1966
The Original Series - Season 1, episode 8 - What Are Little Girls Made Of
Nurse Chapel's long-lost fiance is found - along with his androids.
Original airdate - October 20, 1966
The Original Series - Season 1, episode 10 - Dagger of the Mind
A new treatment for the criminally insane has deadly results.
Original airdate - November 3, 1966
The Original Series - Season 1, episode 9 - Miri
A strange group of children are discovered on an Earth-like planet.
Original airdate - October 27, 1966
The Original Series - Season 1, episode 14 - The Conscience of the King
Kirk suspects Shakespearean actor Anton Karidian as a mass murderer.
Original airdate - December 8, 1966
The Original Series - Season 1, episode 17 - The Galileo Seven
Seven Enterprise crew members go on a shuttle mission with Spock in command.
Original airdate - January 5, 1967
The Original Series - Season 1, episode 21 - Court Martial
Kirk is recalled for a potential court-martial.
Original airdate - February 2, 1967
The Menagerie is largely reedited from The Cage, which we watched a while back, but don’t skip it - after spending so much time with Spock and Pike since, this episode is absolutely essential.
The Original Series - Season 1, episode 12 - The Menagerie, Part I
pock hijacks the Enterprise to return an injured Captain Pike to Talos IV.
Original airdate - November 17, 1966
The Original Series - Season 1, episode 13 - The Menagerie, Part II
The Talosians force Kirk to view Captain Pike's original mission to their world.
Original airdate - November 24, 1966
The Original Series - Season 1, episode 16 - Shore Leave
While on shore leave, the crew's thoughts mysteriously come to life.
Original airdate - November 24, 1966
The Original Series - Season 1, episode 18 - The Squire of Gothos
A powerful entity known as Trelane torments the crew of the Enterprise.
Original airdate - January 12, 1967
The Original Series - Season 1, episode 19 - Arena
Mysterious aliens pit Kirk against a Gorn in a barehanded duel.
Original airdate - January 19, 1967
The Original Series - Season 1, episode 28 - The Alternative Factor
An alien being fights himself across two realities.
Original airdate - March 29, 1967
The Original Series - Season 1, episode 20 - Tomorrow is Yesterday
A time accident leaves the Enterprise a UFO over 20th century Earth.
Original airdate - January 26, 1967
The Original Series - Season 1, episode 22 - The Return of the Archons
A world run by a computer named Landru traps the Enterprise crew.
Original airdate - February 8, 1967
The Original Series - Season 1, episode 24 - A Taste of Armageddon
A computerized war fought by two planets ensnares the Enterprise.
Original airdate - February 22, 1967
The Original Series - Season 1, episode 23 - Space Seed
Kirk meets Khan, a leader of Earth's Eugenics Wars of the 1990s.
Original airdate - February 15, 1967
The Original Series - Season 1, episode 25 - This Side of Paradise
The Enterprise visits a colony where floral spores bring peaceful contentment.
Original airdate - March 1, 1967
The Original Series - Season 1, episode 26 - Devil in the Dark
An unknown monster threatens a critical mining operation.
Original airdate - March 8, 1967
The Original Series - Season 1, episode 27 - Errand of Mercy
Kirk and Spock battle Klingons to free Organia.
Original airdate - March 22, 1967
The Original Series - Season 1, episode 29 - The City on the Edge of Forever
Kirk and Spock go back in time to save McCoy -- and their own universe.
Original airdate - April 5, 1967
The Original Series - Season 1, episode 30 - Operation: Annihilate!
The Enterprise crew must rid planet Deneva -- and Spock -- of deadly parasites.
Original airdate - April 12, 1967
The Original Series - Season 2, episode 7 - Catspaw
Aliens on a mission of conquest hold the crew captive.
Original airdate - October 27, 1967
The Original Series - Season 2, episode 9 - Metamorphosis
The shuttlecraft Galileo makes a forced landing on a world with a single human inhabitant.
Original airdate - November 10, 1967
The Original Series - Season 2, episode 11 - Friday’s Child
The Enterprise crew becomes embroiled in a local power struggle on a tribal planet.
Original airdate - December 1, 1967
The Original Series - Season 2, episode 2 - Who Mourns for Adonais?
The Enterprise is held captive by the Greek god, Apollo.
Original airdate - September 22, 1967
The Original Series - Season 2, episode 1 - Amok Time
Spock undergoes the Vulcan mating ceremony.
Original airdate - September 15, 1967
The Original Series - Season 2, episode 6 - The Doomsday Machine
A machine that destroys planets threatens the Enterprise.
Original airdate - October 20, 1967
The Original Series - Season 2, episode 14 - Wolf in the Fold
Scotty is implicated in a Jack the Ripper-style murder.
Original airdate - December 22, 1967
The Original Series - Season 2, episode 3 - The Changeling
The Enterprise encounters a probe named Nomad.
Original airdate - September 29, 1967
The Original Series - Season 2, episode 5 - The Apple
The crew discovers a paradise controlled by computer.
Original airdate - October 13, 1967
While Mirror, Mirror is the episode that first introduced the Mirror universe, we’ve already been there on Discovery. Enterprise had a two-part episode there too, actually, but that’s one of the ones we skipped for later viewing and will be arriving at shortly.
The Original Series - Season 2, episode 4 - Mirror, Mirror
Kirk, Scott, McCoy and Uhura enter a parallel universe.
Original airdate - October 6, 1967
The Original Series - Season 2, episode 12 - The Deadly Years
Accelerated aging affects the senior officers and threatens Kirk's ability to lead.
Original airdate - December 8, 1967
The Original Series - Season 2, episode 8 - I, Mudd
A takeover leads Kirk to his old nemesis, Harry Mudd.
Original airdate - November 3, 1967
The Original Series - Season 2, episode 15 - The Trouble with Tribbles
The Enterprise is overrun by furry creatures while tangling with Klingons and bureaucrats.
Original airdate - December 29, 1967
The Original Series - Season 2, episode 25 - Bread and Circuses
Spock and McCoy are forced to fight in Roman-like games.
Original airdate - October 13, 1967
The Original Series - Season 2, episode 10 - Journey to Babel
Tensions run high when the Enterprise transports ambassadors to the Babel Conferences.
Original airdate - November 17, 1967
The Original Series - Season 2, episode 19 - A Private Little War
The Klingons provide arms to a peaceful planet and disrupt the balance of power.
Original airdate - February 2, 1968
The Original Series - Season 2, episode 16 - The Gamesters of Triskelion
Three disembodied beings wager on fights staged by prisoners abducted from around the galaxy.
Original airdate - January 5, 1968
The Original Series - Season 2, episode 13 - Obsession
Kirk is determined to hunt down a vampiric entity he failed to destroy in his past.
Original airdate - December 15, 1967
The Original Series - Season 2, episode 18 - The Immunity Syndrome
A giant space amoeba threatens the entire galaxy.
Original airdate - January 19, 1968
The Original Series - Season 2, episode 17 - A Piece of the Action
Kirk investigates a planet with an Earth-like 1920s gangster culture.
Original airdate - January 12, 1968
The Original Series - Season 2, episode 22 - By Any Other Name
Extra-galactic beings commandeer the Enterprise in an attempt to return home.
Original airdate - February 23, 1968
The Original Series - Season 2, episode 20 - Return to Tomorrow
Telepathic aliens take over Kirk and Spock's bodies.
Original airdate - February 9, 1968
The Original Series - Season 2, episode 21 - Patterns of Force
Enterprise is sent to planet Ekos to investigate a disappearance of Federation historian John Gill.
Original airdate - February 16, 1968
The Original Series - Season 2, episode 24 - The Ultimate Computer
Enterprise is used to test the new M-5 computer.
Original airdate - March 8, 1968
The Original Series - Season 2, episode 23 - The Omega Glory
The Enterprise finds a planet devastated by disease that appears to treat the American flag with great reverence.
Original airdate - March 1, 1968
The Original Series - Season 2, episode 26 - Assignment: Earth
The Enterprise goes back in time and discovers a mysterious stranger trying to interfere with 20th-century events.
Original airdate - March 29, 1968