How to get from Athens to Santorini

Fly Aegean.

What constitutes "best"?
Fastest is flying.
Most scenic is ferry.

Even a "conventional" Ferry (Blue Star, with limited seating on Open decks) is not that scenic except for entry into the Santorini "caldera". The so-called "fast-ferries" have no decks to sit on, nor even corridors to walk around... you are stuck in your reserved seat for well over 5 hours.... and very few seats by or near windows. ANd even with the Open Deck Blue Star vessels, after you leave the Pireaus dock area, there is almost nothing to see for many hours except the open sea.

Fly. You have a choice of airlines--Aegean or Sky Express. Both have numerous flights each day.

Ryanair and Volotea have one or two flights as well.

Another vote for flying. Fast, not expensive. Frequent service.

Thanks! We are flying Aegean.