Promotional tariff with Turkish Airlines is valid for flights between 1st of October 2015 till 15th of March 2016. except black out period around Christmas holidays. We have managed to find the cheapest flights mainly in January, February and March 2016. This is based on date of your outbound flight to Hong Kong. Booking has to be done till 15th of June or until sold out. If you want to compare hotel rooms in Hong Kong you may check here.
Booking samples
Netherlands - Hong Kong for €368 (+€22 booking fee)
Brussels - Hong Kong for €419 (+€22 booking fee)
Dublin - Hong Kong from €374
London - Hong Kong for £345
Dublin/Amsterdam - Hong Kong - London for £266
Germany - Hong Kong from €447
Vienna - Hong Kong from €432
Paris - Hong Kong from €410
Helsinki/Copenhagem/Budapest - Hong Kong from €366
Booking sample of cheap return flights from Europe to Hong Kong for €366 here. In this case you would be departing from Helsinki to Hong Kong on 17th of January. Your return flight would be then on 7th of February 2016 from Asia back to Europe.