The Masked Finfoot (Heliopais personatus) has a global population estimated at 1,000 individuals, but very little is known about its ecology. Therefore, the nesting ecology of the Masked Finfoot was studied in the Sundarbans of Bangladesh between 2011 and 2014, and compared to nesting observations from the same area made in 2004. A total of 25 nests were detected in 2011–2014: 56% (n = 14) on blinding mangrove (Excoecaria agallocha), 36 % (n = 9) on sundri (Heritiera fomes) and 8% (n = 2) on cannonball mangrove (Xylocarpus granatum). Factor analysis revealed that 2004 nest characteristics differed from subsequent years. The 2011–2014 nests were built on the periphery of vegetation along narrow creeks of 12.66 ± 3.54 m and located 1.78 ± 0.53 m above water level at high tide. Diameter of nesting tree (2004 = 16.68 ± 5.82, 2011–2014 = 34.19 ± 3.96), nest depth (2004 =16.88 ± 3.09, 2011–2014 = 13.28 ± 3.32) and creek width (2004 = 21.26 ± 9.09, 2011–2014 =12.66 ± 3.54) was significantly different between 2004 and 2011–2014. Reasons for changes in nesting locations are important to determine given the conservation status of the species and altering conditions in the Sundarbans.