|This article or subsection has an associated category.||2151|
|years:||2148 2149 2150 2151 2152 2153 2154
(stardates from 2151.0)
|decades:||2120s 2130s 2140s 2150s 2160s 2170s 2180s|
|centuries:||21st century - 22nd century - 23rd century|
2151 was, on Earth's calendar, the 52nd year of the 21st century, and the second year of the 2150s decade. Although this was a time period before Human formulation of stardates, this era begins with stardate 2151.0.
- Generation ship Alamo discovers the Kitjef system and names it after the children of the discoverers—Kit Carson and Jefferson Davis.
- Annorax invents the temporal exclusion device.
- 16 April: Launch of Enterprise by United Earth's Starfleet.
- April: United Earth makes first contact with the Klingon Empire, Suliban Cabal; discovery of the Temporal Cold War.
- May: United Earth makes first contact with the Axanarri.
- The Enterprise crew discover their first Class M planet, later named Archer IV.
- The Enterprise makes first contact with the Fazi.
- June: United Earth makes first contact with the Andorian Empire, becomes involved in ongoing Vulcan-Andorian cold war; existence of Vulcan spy facility underneath Vulcan P'Jem monastery exposed, destruction of monastery and facility.
- The Vulcan starship, Ti'Mur, makes contact with a Dokaalan unmanned probe. They pass the information unto Admiral Maxwell Forrest who decides not to send Enterprise to investigate. 
- October: United Earth makes first contact with Coridan III.
Promotions and transfers
- United Earth Starfleet Captain Jonathan Archer appointed commanding officer of Enterprise NX-01; Vulcan Subcommander T'Pol transfers from Vulcan Consulate in San Francisco to Enterprise NX-01 to serve as executive officer, Vulcan liason.