Its adviseable to book. You can do this at the Otogar and check out the various bus companies.
Depending on the time you wish to travel you have options to go on the larger coaches with
Kamel Koc,Pammukalle etc or the smaller coach operatives like Bati Antalya or Fethiye Seyhat,
which run more frequently.Current cost is 25tl single fare.Takes 3.5hrs.
Enjoy you lucky people you!!!!