As there is no Airport in Symi, you need to travel first to Rhodes, Kos, or even Athens and then come by boat.
Dodecanese Seaways is the other main ferry line between Rhodes and Symi (and other islands of the Dodecanese). They have two high speed catamarans, the Dodekanisos Express and the Dodekanisos Pride. Although tickets are more expensive, crossing times are faster, whereas the journey takes only 45 minutes. Make sure you either book online first, or arrive quite early for a ticket during the high summer season. You can also board vehicles but you must check for availability in advance.
Apart from InTicket as mentioned above, another good site with Ferries schedules is Danae which you can check here. Also, other smaller boats come to Symi for day trips, in the summer, and you could book a one-way ticket on these. Look out for the Symi day trip boats as you walk along Mandraki harbour.
What Ferries are available from Athens (Piraeus) to Symi and Rhodes?
If you wish to take a ferry from Athens (Piraeus) Port (Gate E1) directly to Symi, then it is best to check online with Blue Star Ferries. The journey from Athens to Symi can take 12 to 18 hours, stopping at various other islands of the Dodecanese en route. You could also board a vehice, if you have one. In Athens you may get to Piraeus either by Bus Line (E96 express) from the Eleftherios Venizelos Airport stopping lastly at the port or by Bus 040 from Omonia / Syntagma Square. Another convenient way is using the subway (blue line from the airport) and then change lines in Monastiraki. Board the green line whose last stop is Piraeus. Finally, there are the Taxis all over Athens which can take you to the port.
Flights to Symi?
As there is no Airport in Symi, you need to travel first to Rhodes, Kos, or even Athens and then come by boat. There are many Flight Companies which are offering flights to these destinations. Below we list some, with links, to help you find available dates (each link will open in a new window).