PLAYER
POS
DOB
CLUB
SINCE
JO
John O'Shea
DF
30.04.1981 (45)
IrelandRetired
—
CO
Callum O'Dowda
FW
23.04.1995 (31)
Ireland
Ferencváros2025
AO
Andy O'Brien
DF
29.06.1979 (47)
IrelandRetired
—
DO
Darren O'Dea
DF
04.02.1987 (39)
IrelandRetired
—
DO
Dara O'Shea
DF
04.03.1999 (27)
Ireland
Ipswich Town2024
LO
Liam O'Brien
MF
05.09.1964 (62)
IrelandRetired
—
KO
Keith O'Neill
MF
16.02.1976 (50)
IrelandRetired
—
MO
Michael Obafemi
FW
06.06.2000 (26)
Ireland Blackpool2026 (Loan)
AO
Andrew Omobamidele
DF
23.06.2002 (24)
Ireland
RC Strasbourg2025
FO
Frank O'Farrell
MF
09.10.1927 (†)
IrelandDeceased
—
EO
Eunan O'Kane
MF
10.07.1990 (36)
IrelandRetired
—
PO
Patrick O'Connell
DF
08.03.1887 (†)
IrelandDeceased
—
AO
Aiden O'Brien
FW
04.10.1993 (33)
Ireland Working2025
JO
Jake O'Brien
DF
15.05.2001 (25)
Ireland Everton2024
JO
Jackie O'Driscoll
MF
20.09.1921 (†)
IrelandDeceased
—
KO
Kieran O'Hara
GK
22.04.1996 (30)
Ireland
Dundee2025
JO
Joe O'Cearuill
DF
09.02.1987 (39)
IrelandRetired
—
LO
Lee O'Connor
DF
28.07.2000 (26)
Ireland Tranmere Rovers2022
MO
Max O'Leary
GK
10.10.1996 (30)
Ireland West Bromwich Albion2026
JO
Jim O'Brien
MF
28.09.1987 (39)
IrelandRetired
—
MO
Mark O'Brien
DF
20.11.1992 (34)
IrelandRetired
—
GO
George O'Callaghan
MF
05.09.1979 (47)
IrelandRetired
—
KO
Kevin O'Callaghan
MF
19.10.1961 (65)
IrelandRetired
—
EO
Eoghan O'Connell
DF
13.08.1995 (31)
IrelandFree Agent
—
AO
Anthony O'Connor
DF
25.10.1992 (34)
Ireland Harrogate Town2022
DO
Daire O'Connor
MF
15.04.1997 (29)
Ireland
Ballymena United2025
DO
Darragh O'Connor
DF
05.08.1999 (27)
Ireland Raith Rovers2025 (Loan)
KO
Kevin O'Connor
MF
24.02.1982 (44)
IrelandRetired
—
KO
Kevin O'Connor
DF
07.05.1995 (31)
Ireland
FC Naples2025
MO
Michael O'Connor
FW
31.07.1998 (28)
Ireland Glentoran2021
PO
Paudie O'Connor
DF
14.07.1997 (29)
Ireland Reading2025
TO
Thomas O'Connor
DF
21.04.1999 (27)
Ireland Peterborough United2025 (Loan)
RO
Roy O'Donovan
FW
10.08.1985 (41)
Ireland
Newcastle Olympic2024
WO
Warren O'Hora
DF
19.04.1999 (27)
Ireland Hibernian2024
CO
Corey O'Keeffe
DF
05.06.1998 (28)
Ireland Stockport County2025 (Loan)
DO
David O'Leary
DF
02.05.1958 (68)
IrelandRetired
—
MO
Mark O'Mahony
FW
14.01.2005 (21)
Ireland Reading2025 (Loan)
CO
Conor O'Malley
GK
01.08.1994 (32)
IrelandRetired
—
OO
Ollie O'Neill
MF
08.01.2003 (23)
Ireland Leyton Orient2024
AO
Adam O'Reilly
MF
11.05.2001 (25)
Ireland Derry City2023
DO
Daniel O'Reilly
DF
11.04.1995 (31)
Ireland Partick Thistle2024
CO
Connor O'Riordan
DF
19.10.2003 (23)
Ireland Doncaster Rovers2025 (Loan)
JO
Jay O'Shea
MF
10.08.1988 (38)
Ireland Brisbane Roar2019
JO
John O'Sullivan
MF
18.09.1993 (33)
Ireland Shelbourne2024
WO
Wayne O'Sullivan
MF
25.02.1974 (52)
IrelandRetired
—
JO
John-Joe O'Toole
MF
30.09.1988 (38)
Ireland AFC Wimbledon2024
KO
Kevin O'Toole
MF
14.12.1998 (28)
Ireland New York City FC2022
AO
Aarón Ochoa
MF
18.04.2007 (19)
Ireland
Málaga2023
MO
Mipo Odubeko
FW
21.10.2002 (24)
Ireland Shelbourne2025
CO
Chiedozie Ogbene
MF
01.05.1997 (29)
Ireland Sheffield United2025 (Loan)