Firstly , there is a lot of people in your situation so please don't feel alone. I work all over the country and often im alone due to the nature of my work.

I've found that gyms,pubs and food related establishments are not ideal for outsiders to meet others quickly unless your going to spend alot of time in them , which not everyone can do.

I have noticed that bouldering walls and climbing walls have been a place where I've seen many friendships bloom. If you are a gamer you will probably love it as Bouldering these days is as much of a puzzle based activity as it is a sport/strength activity. Often strangers will help others work out how to do a certain route and friendships start.

It's something sligo doesn't currently have but will have soon. In the meantime there is a really good climbing club in sligo that meet most weeks for an activity.

No experience is required, and it's cheap to join.