|Date:||Various, but with an apex in the 31st Century|
|Cause:||Use of time travel to alter history|
|Result:||Enforcement of the Temporal Accords|
| Galactic Union
| Temporal Liberation Front|
The Temporal Cold War was a conflict fought between numerous factions from different time periods.
- Galactic Union (Post-28th Century)
- Temporal Liberation Front
- Sphere Builders (26th Century)
- Krenim (2410 and Post-25th Century)
- Na'kuhl (29th Century)
- Vorgon (27th Century)
- Second Terran Empire (briefly)
- Tholian Assembly (22nd and 25th Century)
- Suliban Cabal (22nd Century)
- At some point during the Cold War, the Sphere Builders of the 26th century send several Spheres back in time thousands of years to create the Delphic Expanse as part of their plans to invade and colonize the Milky Way.
- In the early 22nd Century, the Na'kuhl of the 29th Century shared knowledge about the future with selected 22nd century Klingons in the hopes of gaining their allegiance. However, the Klingons did not obey their commands and instead used the information to their own advantage. Among said information was the location of an ancient doomsday weapon.
- The Sphere Builders, able to predict likely futures, discover that their plans to invade the Milky Way will be foiled by their contemporary Federation rivals in the 26th century. They attempt to change history in their favor by earning the trust of the Xindi and tricking them into building a superweapon to destroy Earth, thereby preventing the Federation from coming into being.
- The Cabal destroys a colony on Paraagan II and attempts to frame Enterprise. The humans retrieve evidence proving the Cabal's guilt, but the ship is captured by the Cabal. The Federation from the 31st century tries to rescue Captain Archer, but accidentally alters history and causes the destruction of the human race. Eventually Archer is returned to his own time and Enterprise freed, correcting the timeline.
- A timeship from the 31st century suffers an accident and is left adrift in 2152. Enterprise, the Suliban, and the Tholian Assembly fight each other for the ship, but eventually the timeship is returned to its own time.
- The Xindi complete a prototype of their superweapon, and use it against Earth. Enterprise is sent into the Delphic Expanse to stop them after the Cabal's benefactor warns Enterprise of the threat.
- Enterprise manages to convince the Xindi leadership that they have been deceived; however a number of Xindi-Reptilians and Insectoids are unconvinced and attempt to launch the weapon themselves. They are stopped by Enterprise, the loyal Xindi, and the Andorian warship Kumari. Enterprise is also able to disable the Sphere Network and dismantle the Delphic Expanse.
- A number of Na'kuhl - including their leader, Vosk - are stranded on a alternate 20th century Earth after escaping capture by the 31st century Federation via a temporal conduit which allowed the Na'kuhl one way stealth time travel. They reconstruct the temporal conduit after enlisting the help of Nazi Germany and travel to the 31st century where they defeat the Federation, the Cold War turning 'hot' as a result. This creates the alternate timeline in which Vosk and his group arrived, forming a predestination paradox. However, Enterprise is sent back in time to stop the Na'kuhl from escaping the 20th century, eventually succeeding and restoring history to normal. The Federation believed that this incident has triggered the end of the Temporal Cold War.
- The Na'kuhl in alliance with the Orion Syndicate attempt to disrupt the Babel Conference, kill James Kirk and destroy the Enterprise, however they are stopped by a ship that came from an alternate 2270, in which the plan succeeded, thus restoring the timeline.
- Later this year, the Na'kuhl make an attack on a Tholian Convoy attempting to blame the Federation, however they are stopped by the Defiant and a ship from the year 2270. They also leave a message on the Defiant's computer designated for Leeta.
- Temporal agent Daniels infiltrates a ship from this time period as Ensign Hunter.
- The Na'kuhl attempt to capture the neural parasites from Deep Space K-13, but they are stopped by a Pioneer-class vessel. And would later contact the Klingons, along with the Envoy, and help them during the Battle of Caleb IV.
- The Tholian Assembly is still involved with the Cold War, stealing artifacts such as Wells-class timeships from the future for study.
- “The Doomsday Device”: B'vat, a descendant of the Klingons who met the Na'kuhl, captures the derelict doomsday weapon from the T'Ong Nebula and reactivates it with the intention of using it against the Federation.
- “Sunrise”: The Tholians lure Kal Dano to the present from the 31st century by destabilizing the Lukari star, planning to steel the Tox Uthat. Kal Dano loses the Tox Uthat to the Tholians after repairing the damage to the star, telling the player that these events are tied into the Temporal Cold War.
- “Stormbound”: The Tholians manage to use the Tox Uthat on the star of the Na'kuhl System. Kal Dano and the player subsequently retrieve the device from the Tholian flagship and travel back the 22nd Century, where they hide it in a cave on Risa. After returning to 2410, the U.S.S. Pastak answers a temporal distress call sent by Kal Dano shortly before he vanishes into a time vortex during a renewed fight against the Tholians in the Na'kuhl System. After Cpt. Walker invites the player to the Pastak's bridge, they manage to retrieve Kal Dano's decayed corpse and time capsule, which had traveled back to the early 22nd Century where, a few decades later, the crew of the Enterprise (NX-01) inadvertently activated the capsule's temporal distress beacon, causing it to automatically travel back to 2410.
- “Time and Tide”