Objective <p>This cross-sectional study aimed to characterise the prevalence and severity of intraretinal (IRF) and subretinal fluid (SRF) in in non-arteritic ischemic optic neuropathy (NAION).</p> Methods <p>Two neuro-ophthalmologists assessed optical coherence tomography scans of patients diagnosed with acute NAION at a tertiary neuro-ophthalmology centre between July 2022 and July 2024 for peripapillary SRF, peripapillary IRF, and foveal SRF.</p> Results <p>Sixty-eight eyes (median age 65.0 years, 32.4% female) were seen across a median follow-up of 10.6 weeks (interquartile range 5.8–28.5 weeks). Peripapillary SRF was present in five (7.4%) cases (height range 57.0–216.0 μm), peripapillary IRF in 32 (47.1%, height range 103.0–364.0 μm), and foveal SRF in six (8.8%, height range 51.0–288.0 μm). Peripapillary SRF did not extend beyond a quarter of the distance from the disc margin to the fovea, but peripapillary IRF extended more than halfway in 9 (28.1%) cases. Compared to patients without peripapillary IRF, patients with peripapillary IRF had a greater baseline pRNFL thickness (<i>P</i> = 0.02) and smaller CDRs in the unaffected eye (average CDR, <i>P</i> = 0.002). The presence of foveal SRF was associated with the presence of peripapillary IRF (<i>P</i> = 0.008), greater peripapillary IRF height (<i>P</i> = 0.003), and foveal peripapillary IRF extension (<i>P</i> = 0.003). The presence and severity of peripapillary SRF, peripapillary IRF, and foveal SRF were not associated with initial nor final visual function.</p> Conclusions <p>Peripapillary IRF restricted to the peripapillary region occurs in one-third of acute NAION cases but peripapillary IRF extending more than 50% to the fovea, peripapillary SRF, and foveal SRF are uncommon. Patients with smaller optic discs and more severe disc oedema may be more likely to develop peripapillary IRF and foveal SRF.</p>