A good session with plenty of room sit and watch or participate. Probably not a good place for beginners. The musicians vary wildly on openness to newcomers playing. Usually starts around 9:30 or 10pm.
This is a great pub - it used to be my work local - great food - we had all our work parties there. The sessions are really nice too.
Only on Sunday now
I dropped by Rumms on a Friday night during a visit to Dublin a couple of weeks ago, and there was a popular music band playing. I was told the Irish session only happens on Sunday evenings.
Never mind the session, the pub doesn’t even exist. It’s now called the chophouse or something. Took a 40 minute “ stroll” there in the soft rain armed with fiddle but walk back did me good.