First contacts
This is a list of first contacts between civilizations:

First contact events where the exact date is known

Human (pre-Federation)

Federation (22nd century)

Federation (23rd century)

Federation (24th century)

Federation (Delta Quadrant species encountered during 24th century)

Other species

Species where approximate first contact dates are known

Humans

Denobulans

Vulcans

Federation

Borg

Other species

Unofficial first contacts 
Often species have made contact much earlier than their official first contact dates, in events that become lost in history, are not reported, or whose full significance is not realized at the time.

Human and Federation

Other species

Alternate timelines

First contact events where the exact date is known

Species where approximate first contact dates are known 

de:Liste von Erstkontakten
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