Aberdeen International Airport is located just 6 miles from the city centre and is well-served by various international airlines. It's an easy bus or taxi ride to the city centre.
Buses are provided by First and Stagecoach, both within the city centre and connecting it to various other destinations.
Trains to Aberdeen from elsewhere in Scotland and the UK are provided by Scotrail and LNER. The overnight train from London, the Caledonian Sleeper, also stops at Aberdeen.
Northlink ferries to and from Shetland and Orkney depart from Aberdeen harbour.
Aberdeen City Council has published an excellent public transport guide for getting around the city once you arrive.
Those wanting to make the journey into a destination of its own could do a lot worse than taking the Aberdonian service from Edinburgh on the Tornado steam locomotive. The route is spectacular, crossing the Forth bridge and continuing along the coast.