2409

 is the year during which the events of Star Trek Online are set up until the mission.

Early events

 * The colony on Virinat is destroyed by the Elachi and Tal Shiar.
 * The Borg start their first incursion into the Alpha and Beta Quadrants in more than 30 years, most notably on Defera Prime and Vega IX.
 * Daniels recruits temporal agents from the 2257 and 2270 and brings them to 2409.
 * House Mo'Kai, led by Matriarch J'Ula, arrives from 2257.
 * Franklin Drake escapes Klingon custody.
 * The Federation-Klingon War, in its 4th year, rages across the border areas. Ambassador B'vat attempts to use illegal weapons and time travel to secure a Klingon victory.
 * The Fek'Ihri return to attack Qo'noS.
 * The House of Torg gets dissolved.
 * The Romulan Insurgency ends, beginning the Romulan Civil War.
 * The Romulan Republic, a faction formed by D'Tan, settles on New Romulus.
 * Devidian incursions on and near Drozana Station lead to an investigation that reveals that Devidians have been feeding on crews from the 23rd century. The incursions are ended with the destruction of Driffen's Comet

Thalaron Investigation

 * The Federation and Klingons send crews to Nimbus III to track down thalaron triggers.
 * Hassan the Undying is defeated, breaking the control of the Orion Syndicate over the planet.
 * The triggers are removed from Nimbus by the Reman Resistance.
 * Empress Sela attempts an invasion of Vulcan.
 * The Romulan Star Empire is found to be experimenting with Borg technology.
 * Former Empress Taris is captured and her Iconian gateway destroyed after her involvement in the Hobus supernova is discovered.
 * Reman with aid from Federation/Klingon forces, defeat Sela and Hakeev's base on Brea III.
 * Sela is kidnapped by the Iconians.

Later events
The below could potentially take place in 2410.
 * The True Way form an alliance with Admiral Leeta of the Mirror Universe.
 * The New Link discover that Laas has hidden the truth from them concerning the state of the galaxy.
 * Deep Space 9 is occupied by temporally displaced Dominion forces.
 * The KDF, Starfleet and the Romulan Republic launch their new flagships.
 * The Female Changeling is released from Starfleet custody.

Mission order

 * The Romulan Tutorial is said to occur in January 2409, two weeks before the Starfleet tutorial . The Klingon tutorial  is undated, but presumed to occur around the same time, but  presumably concludes before the original mission order of  in the Klingon War arc due to Franklin Drake's presence.
 * and occur at the same time, meaning the Vengeance and Romulan Mystery arc run roughly in parallel, with no KDF events happening between  and.
 * is the last event certain to have taken place in 2409.
 * Some mission chains are not unlocked until endgame, but are set in 2409;
 * Wasteland is not unlocked for Federation and KDF players until endgame, but occurs at the same time (before ) in the game's story as it does for Romulans.
 * Lost Dominion and Cold War and Spectres were originally set in 2409, although are now not playable until Level 65. In terms of timeline, Lost Dominion occurs at the end of Cardassian Struggle and is immediately followed by Cold War, while Spectres occurs during the Klingon War arc.

Notable deaths

 * Alexander Rozhenko, son of Worf
 * Borg Queen
 * Admiral B'vat, son of Warat
 * Donatra
 * Colonel Hakeev
 * M'ven, son of Drex
 * Ambassador Sokketh
 * S'gen, son of Torg
 * Captain Taggart
 * Commander Temer