Just returned from a cruise oboard Quest from Istanbul to Piraeus. Embarkation in Galataport was a breeze! All posts above are correct, but... if you have a taxi driver that knows his/her way around, you will be dropped off underground which is where the actual terminal is. The taxi drove inside the terminal, was inspected by security guards and then allowed to proceed to the actual Azamara check-in terminal. Our suitcases were picked up curbside right next to where we got out of the taxi. 20 mins later we were onboard. The taxi company we used is Welcome Pickups.