If you only have one day in Izmir, the park may not be for you, as there are many other things to see. But I feel like the animal park is one of Izmir's hidden gems. I have been to many zoos in the US, and while they have been nice, they are often crowded. This park is spacious, clean, and well decorated. I have never seen it crowded, but if you would like to experience it on its least busy times, go in the morning, on a weekday, or on a cool/overcast days.
What keeps me going back to the park though is the amazing views of the animals. They are frequently active and close to viewing areas. During our visits, the lions, pumas, tigers, bears, wolves, and hyenas often come within inches of the viewing areas. In my opinion, these up-close encounters are the best part of the park.
The park is also recognized as having the first and only elephant family in Turkey. They are also the only Turkish zoo with a rainforest enclosure.
How to get there:
If you are coming from Alsancak or Konak, take the ferry to Karşıyaka. When you walk out of the ferry station, cross the street, and walk to your left until you reach the Osman Bey Parkı stop.
The 777 bus will take you to the animal park. It takes about 25 minutes to get there, but it is very easy to find as the animal park is the last stop. The bus comes frequently on weekends (about every 15-20 minutes), but less so on weekdays (about every 45 minutes). Note: this bus gets very busy on Wednesdays as it passes by a very popular bazaar.
For the most up to date hours, you can visit the website below, choose 777 from the dropdown, and click "Hareket Saatleri"
Cost (as of 2014):
When you get off the bus, you will walk to a ticket office. They will give you a coin that will act as your ticket.
3TL for adults
1TL for students
Small children are free
Note: there are separate lines for adults and students. The people at the gate will help you though.
Closes: Varies seasonally
Winter (October 25 - March 1) - 4:30pm
Spring (March 2 - March 30) - 5:30pm
Summer (April 1 - September 21) - weekdays 6:30pm; weekends and holidays 7:30pm
Fall (September 22 - October 24) - 5:30pm
Outside food allowed
Park Website: http://www.izmirdogalyasamparki.org.tr/