I need to get from Atatürk Airport landing at around 6 to the port for the BUDO catamaran.
Would a bus or taxi be a better choice?
Also, which buses would be best and would I have to book in advance (preferably with fares and times)?
Rome2Rio comes in handy for this:
They suggest 3 routes:
which would be 'best' depends on you, your travel plans and time and money, but as a general rule - if you're not used to travelling in a new country, choose the option with fewest changes.