Is a same-day trip to The Land of Legends realistic from a hotel in Side, Kemer or Alanya?

Those times are averages with room left for normal traffic, and they stretch in high summer. If you are returning the same day, count the road twice: from Side that is roughly two and a half hours of driving in total, from Kemer around three, from Alanya closer to four. Travelling with small children, that figure shapes the rest of the day.

There are two practical ways to handle the longer origins. One is to loosen the return rather than cut the visit short — setting the pick-up at a later hour from the start is easier than waiting at the gate. The other is to stay a night in the area and travel back the next day, in which case the transfer is planned across two separate days. Whichever you choose, the pick-up and drop-off points and the times are written into the booking.