Kangaroos are wild animals.
While you will come across them if you are driving in rural areas, do not approach them.
While most will simply run away, some may enter a more defensive posture especially if there are young (joeys) nearby.
A kick from an adult can kill a human ( http://www.amazingaustralia.com.au/animals/kangaroo_attacks.htm ).
Kangaroos can be mean vicious creatures.
When I was growing up as a kid in Australia, we were cautioned away from getting anywhere near them.
The best and safest way to get a selfie with a kangaroo that isn't a cardboard cutout is to go to a zoo that has a petting zoo component.
Instead of kangaroos, they often pick the smaller/friendlier cousin, the wallaby ( http://animals.howstuffworks.com/mammals/wallaby-vs-kangaroo.htm ).
This is just one of many petting zoos that have wallabies: http://www.featherdale.com.au/# =
travel.stackexchange.com/users/17153/RoboKaren
It depends on how close you intend on getting for your selfies.
If you insist on approaching closely, I would only do so in a controlled environment.
If you're willing to have your selfie with the kangaroos a dozen or more metres in the background, you'll be fine.
As to where you're able to do so, just about every major town or tourist location has some location where you can get close to kangaroos - patting or hand feeding, either of which would allow selfie opportunities.
Some examples include: Sydney has Taronga Zoo (free roaming kangaroo area) and Featherdale Wildlife Park Melbourne Brisbane Cairns and Kuranda Alice Springs
Even the Whitsundays Searching specifically for whereever you may be visiting would almost undoubtedly find somewhere, as all international airports and ports would have somewhere within an hour or less.
Of course, you could just go golfing.
Mareeba Golf Course.
Credit:
Sweetwater Lodge Yamba Golf Course.
Credit: Shelley Street Beach House Anglesea Golf Course.
Credit: Anglesea Golf Club
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The Cairns Tropical Zoo has a Kangaroo enclosure: Spend time in our kangaroo area.
Around 60 tame
Eastern Grey kangaroos spend their day meeting visitors, eating from your hand and lazing in the heat of the day.
I can confirm that they will let you get relatively close if they are in the right mood, but not necessarily for the kind of "hugging"
selfie
you'd take with a human.
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The Lone Pine Koala Sanctuary in Brisbane also has a kangaroo enclosure
where you can hand-feed kangaroos, including (according to their website)
Red Kangaroos and Eastern Grey Kangaroos.
I visited many years ago and can confirm that they will eat out of your hand; however, selfies were not a thing then, and so I didn't try to take one.
travel.stackexchange.com/users/31165/Michael Seifert
If you are traveling to Melbourne, I recommend you visit Healesville Sanctuary
, it's about an hour east of Melbourne, they have Kangaroo's they are quite used to people.
http://www.zoo.org.au/healesville/animals
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I went to the Featherdale Wildlife Park outside of Sydney when I was about 16.
It was great and plenty of exotic(by
my standards) animals running around that could be fed and touched.
However, I don't recall any kangaroos that were free roaming in the park
, I think they were all in enclosed spaces, but plenty of small wallabies running around like goons.
travel.stackexchange.com/users/31905/JessePinkman
Featherdale in Sydney has wallabies and possibly roos.
Bonorong, just outside Hobart, has both.
In fact, they give you a bag of food for them upon entry.
They seem to be very people friendly and don't mind you petting them.
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Cleland Wildlife Park in Adelaide has tame Kangaroos for selfies.
travel.stackexchange.com/users/12829/GreenAsJade
I see a lot of people doing this. I believe this is not safe, isn't it?  Where can I do this?
Where can I take a selfie with kangaroos in Australia?
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travel.stackexchange.com/users/21894/Machado
Unless you are a dozen or more metres from the kangaroo, it is better to do this in a controlled environment with tame kangaroos, which you can often pat and hand-feed. The Lone Pine Koala Sanctuary  in Brisbane also has a kangaroo enclosure, Featherdale in Sydney has wallabies and possibly roos and Cleland Wildlife Park in Adelaide has tame Kangaroos for selfies. If you are traveling to Melbourne, you can also visit Healesville Sanctuary. The safest place to take a selfie with a kangaroo is in a controlled environment and there are many throughout Australia. Featherdale in Sydney, Cleland Wildlife Park in Adelaide and Healesville Sanctuary in Melbourne all have kangaroos and wallabies that are used to human contact. Taking a selfie with wild kangaroos, however, is considered quite dangerous and it is recommended not to get too close to them.
It is possible to take a selfie with a kangaroo in the wild but it is not safe to get very close to them. For a close-up selfie, a controlled environment is recommended. Most tourist locations have places where tourists can get close to kangaroos. These included Healesville Sanctuary in Melbourne, Featherdale in Sydney and Cleland Wildlife Park in Adelaide.