I am planning to travel Europe with my friend in November/December this year. I will be 18, however, she will only be 16. Will she be able to stay in hostels if she is with me or do they all require they all guests to be 18+? Hostels are the best option for us because we are on a tight budget and can't afford to stay in hotels and airbnb for the entirety of the trip. We are mainly looking at hostels in Austria and Hungary.

I suspect the answer would be yes since I seem to recall folks staying in hostels with their children but you should call the hostels and ask.

What is your back up plan if they say no?

If you are 18, than that will be fine. My son stayed in several hostels last summer, when he was 17. His friend was 18. They had no problem. Be sure she has a permission from her parents to travel - this is sometimes asked at the borders. Better to have it just in case they ask.

Treat yourselves to YHA membership cards and stay in their hostels . These are meant in particular to accommodate young people (although nowadays they take all ages) and offer a tad more security than private hostels.

I don't think the issue of kids with their parents is analagous to two teenagers on their own. Of course people under the age of 18 are allowed in hostels, many school groups use them, for example, with a "chaperon" but they are not on their own.

I'd just check out the ones you are interested in, as I know some do NOT allow people under 18 to check in (like MIJE in Paris) on their own, even if they are allowed in a school group. Same for AIJ hostels in Paris, you cannot check in and have a booking if you are under 18.

May be different in Austria, I'm not familiar with those. But I wouldn't just assume you can go into any hostel and do that.

Here is one in Vienna, for xample, a nice central one and they require a specific attestation form from the parents
https://www.meininger-hotels.com/en/...t/infos-forms/

I'm sure you can see the potential issues with this -- runaways, sex trafficking, etc., if hostels allowed any underage person with someone else to stay there.

My son stayed in a number of hostels in different countries when he was 17, with an 18-year old friend - it wasn't a problem. But do check with the places where you want to stay.