They are from Egypt, Nigeria and Ghana and were abducted by the organisation in its stronghold city of Sirte.
Bekhit Nageh Efrank Ebeid, Sekyere Kofi Frimpong and Aedola Ibrahim are being held in an unknown location and IS has not made any demands for ransom.
Passport images of the group have been posted online by the militants.
Sekyere Kofi Frimpong
Adeola Ibrahim
Bekhit Nageh Efrank Ebeid
Islamic State is feared to be expanding its presence beyond the Middle East and into parts of Libya.
In April the group released two videos showing the murder of 30 Ethiopian Christians in Libya.
15 of them appeared to be beheaded on a beach, whilst the other 15 were shot in the head in a desert.