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
Dara O'Shea
DF
04.03.1999 (27)
Ireland
Ipswich Town2024
DO
Darren O'Dea
DF
04.02.1987 (39)
IrelandRetired
—
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
Jackie O'Driscoll
MF
20.09.1921 (†)
IrelandDeceased
—
JO
Jake O'Brien
DF
15.05.2001 (25)
Ireland Everton2024
JO
Joe O'Cearuill
DF
09.02.1987 (39)
IrelandRetired
—
KO
Kieran O'Hara
GK
22.04.1996 (30)
Ireland
Dundee2025
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
OO
Owen Oseni
FW
07.05.2003 (23)
Nigeria Plymouth Argyle2025
AO
Aarón Ochoa
MF
18.04.2007 (19)
Ireland
Málaga2023
AO
Adam O'Reilly
MF
11.05.2001 (25)
Ireland
Derry City2023
AO
Anthony O'Connor
DF
25.10.1992 (34)
Ireland Harrogate Town2022
AO
Armstrong Oko-Flex
MF
02.03.2002 (24)
Ireland
Levski Sofia2026
CO
Chiedozie Ogbene
MF
01.05.1997 (29)
Ireland Sheffield United2025 (Loan)
CO
Connor O'Riordan
DF
19.10.2003 (23)
Ireland Doncaster Rovers2025 (Loan)
CO
Conor O'Malley
GK
01.08.1994 (32)
IrelandRetired
—
CO
Corey O'Keeffe
DF
05.06.1998 (28)
Ireland Stockport County2025 (Loan)
DO
Daire O'Connor
MF
15.04.1997 (29)
Ireland Ballymena United2025
DO
Daniel O'Reilly
DF
11.04.1995 (31)
Ireland Partick Thistle2024
DO
Darragh O'Connor
DF
05.08.1999 (27)
Ireland Raith Rovers2025 (Loan)
DO
David O'Leary
DF
02.05.1958 (68)
IrelandRetired
—
DO
David Okagbue
DF
05.10.2003 (23)
Ireland Peterborough United2025
EO
Emmanuel Osadebe
MF
01.10.1996 (30)
Ireland Barnet2025
EO
Eoghan O'Connell
DF
13.08.1995 (31)
IrelandFree Agent
—
GO
George O'Callaghan
MF
05.09.1979 (47)
IrelandRetired
—
IO
Ike Orazi
FW
11.06.2007 (19)
Ireland Stade Reims2024
JO
Jay O'Shea
MF
10.08.1988 (38)
Ireland
Brisbane Roar2019
JO
Jim O'Brien
MF
28.09.1987 (39)
IrelandRetired
—
JO
John O'Sullivan
MF
18.09.1993 (33)
Ireland Shelbourne2024
JO
John-Joe O'Toole
MF
30.09.1988 (38)
Ireland AFC Wimbledon2024
KO
Kevin O'Callaghan
MF
19.10.1961 (65)
IrelandRetired
—
KO
Kevin O'Connor
MF
24.02.1982 (44)
IrelandRetired
—
KO
Kevin O'Connor
DF
07.05.1995 (31)
Ireland
FC Naples2025
KO
Kevin O'Toole
MF
14.12.1998 (28)
Ireland New York City FC2022
MO
Mark O'Brien
DF
20.11.1992 (34)
IrelandRetired
—
MO
Mark O'Mahony
FW
14.01.2005 (21)
Ireland Reading2025 (Loan)
MO
Mazeed Ogungbo
DF
20.10.2002 (24)
Ireland Eastbourne Borough2025
MO
Michael O'Connor
FW
31.07.1998 (28)
Ireland Glentoran2021
MO
Mipo Odubeko
FW
21.10.2002 (24)
Ireland Shelbourne2025