Gas measurements using unmanned aerial vehicles, or drones, were undertaken at Turrialba volcano, Costa Rica, and Masaya volcano, Nicaragua, in 2016 and 2017. These two volcanoes are the largest time‐integrated sources of gas in the Central American Volcanic Arc, and both systems are currently extremely active with potential for sudden destabilization. We employed a series of miniaturized drone‐mounted instrumentation including a mini‐DOAS, two MultiGAS instruments, and an optical particle counter, supplemented by ground‐based measurements. Payloads were typically 1–1.5 kg and flight times were 10–15 min. The measurements were both accurate and precise due to the inherent sensitivity of the instrumentation and the high gas concentrations, which the drones were able to sample. The quality of data obtained by our drones was comparable to that obtained by our ground‐based measurements. At Turrialba in April 2017, we measured an average SO₂ flux of 1,380 ± 280 T/day, CO₂/SO₂ of 6.5, and H₂O/SO₂ of 27.8. Using these values, we calculated a CO₂ flux of 6,170 T/day and an H₂O flux of 10,790 T/day. At Masaya in May 2017, the average SO₂ flux was 1,560 ± 180 T/day, with CO₂/SO₂ of 3.9 and H₂O/SO₂ of 62.3, giving a mean CO₂ flux of 4,150 T/day and mean H₂O flux of 27,330 T/day. The elevated carbon and water fluxes and ratios are indicative of underlying magmas that are enriched in these components, resulting in the high levels of activity observed.