Veteran pilot Juha-Pekka Keidasto who is flying the plane says he is not superstitious or scared of flying on Friday the 13th.
Flight 666 has been a scheduled route from Copenhagen Airport (CPH) in Denmark to Helsinki Airport (HEL) in Finland for a number of years.
Today marks the day the Nordic airline has chose to retire the number after flying more than 21 times on Friday 13 since 2006.
"We're growing, so we need more flight numbers." the company explained via Twitter.
This is the 21st time the flight has taken place on Friday 13 since the operators started the AY666 route in 2006.
Finnair said the flight marked the final time Flight 666 will make the trip on a Friday the 13th, as a reordering of flight data is causing the flight to be renumbered to 954. He had earlier said, "It has been quite a joke among the pilots. It's only a coincidence for me". The Flight 666 will depart from the Danish capital at 1:20 pm and will arrive in Helsinki around 4 pm.
Finnair insists it isn't scrapping the spooky number because of fears from superstitious customers.
The flight has landed on Friday 13 a total of 21 times.