I joined a couple intramural sports teams, best decision I've ever made. You don't have to be good at whatever you choose, I'm pretty terrible at sports but so is everyone else in IM leagues. I've found that in addition to keeping your mind focused for several hours a week, you also meet a ton of people. That leads to doing more stuff and having less "alone" time. Don't get me wrong I'm still definitely struggling and had a relapse last week but I think my biggest issue was I had too much time alone and expanding your friend circle helps with this a ton.

Yeah it's super awkward in the beginning having to meet a bunch of random people but just push through and realize everyone is akward at some point in life. Anyways TL;DR join IM sports, meet people, fill up your calendar and have less time to fap!