The 2023-24 defensemen for the Islanders included Sebastian Aho, Samuel Bolduc, Robert Bortuzzo, Dennis Cholowski and Trevor Cosgrove.

	NO.	NAME	POS	HEIGHT	WEIGHT	DOB	AGE	BIRTHPLACE
1	25	Sebastian Aho S. Aho	D	5'10"	186	2/17/1996	27	Umea, Sweden
2	4	Samuel Bolduc S. Bolduc	D	6'4"	220	12/9/2000	23	Laval, Canada
3	41	Robert Bortuzzo R. Bortuzzo	D	6'4"	216	3/18/1989	34	Thunder Bay, Canada
4	7	Dennis Cholowski D. Cholowski	D	6'2"	210	2/15/1998	25	Langley, Canada
5	68	Trevor Cosgrove T. Cosgrove	D	6'0"	200	6/4/1997	26	Exeter, NH
6	8	Noah Dobson N. Dobson	D	6'4"	194	1/7/2000	24	Summerside, Canada
7	43	Aidan Fulp A. Fulp	D	6'3"	210	2/29/2000	23	Westfield, IN
8	77	Zsombor Garat Z. Garat	D	6'1"	203	7/27/1997	26	Budapest, Hungary
9	49	Isaiah George I. George	D	6'0"	195	2/15/2004	19	Oakville, Canada
10		Dennis Good Bogg D. Good Bogg	D	6'1"	191	3/2/2004	19	Stockholm, Sweden
11	42	Seth Helgeson S. Helgeson	D	6'4"	220	10/8/1990	33	Faribault, MN
12	33	Grant Hutton G. Hutton	D	6'3"	206	7/25/1995	28	Carmel, IN
13	61	Christian Krygier C. Krygier	D	6'2"	192	5/5/2000	23	Orlando, FL
14	78	Artem Kulakov A. Kulakov	D	6'2"	198	2/14/2003	20	Bolshoy Kamen, Russia
15	34	Paul LaDue P. LaDue	D	6'3"	205	9/6/1992	31	Grand Forks, ND
16	24	Scott Mayfield S. Mayfield	D	6'5"	220	10/14/1992	31	St. Louis, MO
17	45	Travis Mitchell T. Mitchell	D	6'3"	207	11/25/1999	24	South Lyon, MI
18	58	Calle Odelius C. Odelius	D	5'11"	185	5/30/2004	19	Nykvarn, Sweden
19	3	Adam Pelech A. Pelech	D	6'3"	210	8/16/1994	29	Toronto, Canada
20	6	Ryan Pulock R. Pulock	D	6'2"	216	10/6/1994	29	Dauphin, Canada
21	2	Mike Reilly M. Reilly	D	6'1"	196	7/13/1993	30	Glenview, IL
22	28	Alexander Romanov A. Romanov	D	6'1"	215	1/6/2000	24	Moscow, Russia
23	2	Robin Salo R. Salo	D	6'2"	190	10/13/1998	25	Espoo, Finland
24		Zachary Schulz Z. Schulz	D	6'1"	195	6/14/2005	18	Ann Arbor, MI
25	41	Vincent Sevigny V. Sevigny	D	6'3"	195	4/14/2001	22	Quebec, Canada