Santorini - Student Traveling Alone - Any Group Tours for 2 Days?

I see a few tours from Athens to Santorini that might be good.

https://www.davestravelpages.com/2-days-in-santorini-what-to-see-and-do/

https://santorinitours.org/

Young people travel alone all over Europe. Unless your daughter is completely clueless she'll be fine. As long as she exercises common sense and doesn't take any obvious chances going someplace sketchy with strangers she'll be fine on her own. There are hostels on Santorini where she can mix with others her own age without the structure of a tour, something I'm sure she'll appreciate.

https://www.wsaeurope.com

Rick Steve’s son Andy does this exact thing, runs 2 to 3 night tours for students who are studying abroad. I didn’t see Greece on there but it might give her a place to start.

Also, has she talked to the study abroad coordinator onsite? That person may be able to help match her up with a travel mate. Or, can she put up a notice on a board, or make a post on social media (e.g. if her study abroad group has a Facebook page) to solicit a travel mate?

You have not stated when she wants to go ... if she is in Rome NOW, and will return before early spring, there may not be tours available to her since its way way off-season. We can't really advise well without info on timing.

If she's getting along okay on her program, she'll probably be fine doing this solo. She can stay in a hostel once she arrives so that she meets people to spend time with, or she can do things on her own. It doesn't sound crazy at all; I know I did this kind of thing regularly at that age. It's a great growing experience and very manageable with normal safety precautions.

A college aged adult should be fine traveling away for a weekend alone. No chaperon required.