In the summer of 2016, we observed a pair of Charadrius melodus (Piping Plover) successfully hatch 2 nests at Fire Island National Seashore and fledge chicks from both broods. Double brooding is rare among Piping Plovers, and fledging chicks from both broods is rarer still. In 2017, we observed male and female siblings, 1 individual hatched from each of the double brood nests, incubating the same clutch of eggs on Westhampton Island. Although double brooding has been noted before in this species, this is the first observation of subsequent inbreeding from such an observation on the Atlantic Coast. This observation is unlikely to be evidence of widespread inbreeding within Piping Plover populations due to little evidence of allelic diversity problems in past genetic studies.