Extravascular lung water (EVLW) increases in healthy adults upon exposure to high altitude, likely due to increased pulmonary vascular resistance (PVR). Older individuals experience increased PVR during exercise, which may be exacerbated by trekking at high altitude. This study aimed to determine whether EVLW development is greater in older versus younger adults during graded altitude exposure. Fourteen younger (32 ± 6y) and 12 older (58 ± 5y) healthy adults completed an 11-day trek of Mount Kilimanjaro. EVLW was assessed at rest via comet tails prior to the trek in Moshi (950 m), at Shira Camp (3505 m), at Barafu Camp (4837 m), and post-descent. An increase in altitude from Baseline to Barafu tended to increase the proportion of participants with mild EVLW (p = 0.06). A higher proportion of older versus younger individuals tended to show mild EVLW at Barafu (56 vs. 14%, p = 0.06). In conclusion, EVLW formation may be more common in older adults trekking at high altitude. However, the presence of EVLW in older adults was subclinical.