O'Neill's St Mary Street is a large two-floor Irish pub in the heart of Cardiff city centre, a short walk from the Principality Stadium, accommodating up to 500 across the building. It pairs bold pub food, burgers and pizza with cold pints, big-screen sport and a strong live-music calendar: local talent plays every weekend, there's live music every Thursday and Sunday, regular Irish music nights, and a resident DJ keeping the room going late. The upstairs room is also available for private hire. A busy, high-capacity city-centre venue that's a reliable booking for covers, Irish-trad and party acts.
Cardiff · Every Tuesday · Free
O'Neill's St Mary Street Open Mic
Cardiff's tuesday open mic.
Open mic at a glance O'Neill's St Mary Street · Cardiff
Tuesday
Open mic night
May 2026
Listed since
26 Jul
Last verified
Free
Entry
—
Sign-up time
Community
Listing status
Run a Cardiff open mic? List it free — verified within 48 hours
Last updated: 2 June 2026
O'Neill's St Mary Street Open Mic — Quick Facts
We need your help verifying thisWas this open mic on recently?10 seconds, no signup
The Details
Everything you need before you turn up
DayTuesday
Start20:00
Sign-up walk-in
Slot length–
EntryFree · all ages
Capacity–
Performer typesMusic
Sound engineerBYO / hire on the night
View on map
Where
O'Neill's St Mary StreetCardiff CF10 1DW
Cardiff — check venue website for parking and nearest station.
Contact
Walk-in sign-up only
No advance booking
Host: in-house team
Highlights
Free entry for all
PA system provided
Walk-in sign-up
Music welcome
How do you rate this open mic?One tap, no sign-up required.
Spotted something wrong with this listing?Closed, moved night, different start time? Let us know and we'll re-verify within 48 hours.
What’s on in Cardiff this week — or see what’s on across the UK.
About O'Neill's St Mary Street
About This Open Mic
Every Tuesday in Cardiff
Kicks off at 20:00
Free entry for performers and audience
Slot length — we’re on it, no info yet
PA provided — BYO instrument
Part of the Cardiff open mic directory
The Night
O'Neill's on St Mary Street is a big Irish bar in the heart of Cardiff with a 500-capacity music room upstairs that runs live bands several nights a week. Older listings mention regular open-mic nights, but we couldn't pin down a current recurring day or time, the published weekly schedule leans to live bands, quiz and karaoke. Check with the venue before turning up to play.
What's on stage — equipment and backline at this venue, verified regularly.
PA + monitors
Drum kit
Guitar amp
Bass amp
Keys / keyboard
Vocal mics
In-house engineer
The Night at a Glance
How O'Neill's St Mary Street’s Tuesday night runs.
20:00Kick-off
23:00Venue closes
Every Tuesday Free entry
Find O'Neill's St Mary Street
Cardiff CF10 1DW
Planning Your Tuesday Night
Arrive early to sign up for a slot. Entry is free and the open mic typically runs until late. A PA is provided — bring your own instrument and amp.
Part of the Cardiff live music scene.
What should you charge for paid gigs?Most open mic musicians are ready for paid work sooner than they think. Check live UK rates by role, city, and venue size.
Try the Rate CalculatorCommon Questions
Seven things people ask before turning up at Cardiff's O'Neill's St Mary Street open mic.
Walk-in sign-up only, opens at . Arrive early — slots fill on the night. See other Cardiff open mic nights for alternatives.
PA + vocal mic provided. BYO instrument and amp.
Slot length varies — check with the host.
Yes — free entry for performers and audience. Most Cardiff mics are free; browse the list.
Solo and duo acts work best given the gear available; ask the host before bringing a full band.
Cardiff CF10 1DW.
Mostly fellow musicians, friends and Cardiff regulars across the Cardiff open mic scene. Cardiff open mic crowds tend to listen attentively.
Keep up with Cardiff
One email a week with live music near you. Free, and it keeps grassroots rooms full.
Help keep grassroots venues open in Cardiff
—A UK venue stops hosting live music every 5 days — and turning up is what keeps a room open. Get a free weekly email of gigs in Cardiff. Unsubscribe any time. Privacy.
See what’s on in Cardiff over the next four weeks →
Booking or playing in Cardiff? The GX Index publishes what UK gigs actually pay, by city, band size and venue type, and the GX Index reports set out the methodology and the sample behind every figure. Both are free to read and free to cite.
Keep exploring: the UK gig directory for what's coming up, the venue directory for rooms that book live music, the open mic finder for recurring stage time, and what's on across the UK this week. The blog covers pricing, contracts and getting booked, and about GigXchange explains who runs it and why. Something not right on this page? Tell us — or start on the home page.
Run an open mic in Cardiff?
Add yours to the directory free. 2-minute submission, verified within 48 hours. Reach 1,000+ Cardiff musicians.
Looking for paid gigs, not open mics?