The sci-fi drama, which stars Hermione Norris and Eric Mabius, was shifted to Sunday night to complete its eight episode run after ratings fell to just 2.6 million. Responding to "unhappy viewers", the corporation said that the viewing figures did not "justify" leaving the programme where it was.
"BBC One commissions a large number of new drama series each year and inevitably there will be some that do not engage as wide an audience as we would like them to," a statement said. "We are proud to have brought this original and high quality drama to the audience but unfortunately it did not engage enough of them to justify playing the full series out in a 9pm slot.
"We realise that many viewers enjoyed the series and apologise to them for any disappointment or inconvenience caused by the change of slot to 10:25pm on Sunday."
The final episode of Outcasts will be broadcast this Sunday.
> Outcasts writer responds to critics