Winter season has great discounts and the city pass is definitely the way to go if you're an out of town visitor
If you are plan on going more than a few times a year consider getting the membership it save you money plus you can visit a bunch of other zoo with the same pass.
I went with the city pass as well. City pass is $76 for five attractions in Atlanta. However, the Zoo Atlanta tickets are $28 for adults, $20 for children, $26 for senior, $24 for students and free for babies and military.
I went with the city pass, but I think they are $27 for adults and $25 for kids.
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