Best hobbies for a 30 year old guy to meet single women?

If you need want to meet gamey socialists, try volunteering to help the underprivileged, homeless people, mistreated animals etc

If you prefer a budding Maggie Thatcher, start a collection of Ferraris.

But seriously, anything where there is group interaction, learning a skill or an art, new way to exercise, book clubs, dancing, hillwalking, local history etc.

And I wasn't joking about the volunteering.....

https://www.tagrugby.ie/ITRA-Leagues.html

Came here to say dance class too lol, know two fellas that it worked out well for.

Amateur theater. Decent ratios there.

Another vote for hillwalking. I met my wife on a walking holiday, and after we got together we regularly sent our single-and-looking friends off on hillwalking holidays. Very impressive strike rate!

Dog walking with a cute pooch, if you don’t have one borrow one, a friend used to do this in beer gardens with a dog on an extendable lead, it was like fishing - let out that lead, wait for the bite and then reel it in slowly - always something on the other end. Think big cuddly dog though, not something like a jack russell. Now I’m not dissing JRs - have one myself, great little characters, but I have a Labrador too and the interest in the lab shown is much greater.

Otherwise,

I’d say hill walking is not a bad one, my parents are in a club, and I’ve gone with them a few times and there always seems to be a few singles around.

Sailing is not a bad one either, there always a bit of social in sailing clubs post races, and some singles hanging around.

Running can be a great social sport if you do the organised 5, 10 km runs etc. There is always plenty of social and banter on the way around and at the end, everybody happy out on the endorphin buzz. I’ve met my own lovely fiancée on a run. I’ve not done park runs, but that might be an opening.

Become a nun in an enclosed order.

Yeah I would have thought so. Also something you could get by in without any great talent or being massively passionate about, unlike some of the other stuff suggested here.

Swinging, I'm sure some googling will find you a club

That movie is a load of crap. Why would you date a single mom? Single moms have usually a list of failed relationships. You are going to the bottom of her list of priorities. There is always drama with the EX. Kids are probably going to hate you and tell you often enough "your not my daddy" and "why are you in my house?". Then despite contributing to kids lives you have no legal standing. You are probably going to have to get involved with visitation/custody/family court. I have an associate (fair weather friend) who is one of them women and she is nothing but hard work. You dont really need that drama in your life. Start out on a green field.

Steer clear of Fine Gael women though, apparently they haven't mastered it...