As an adult, D. fascicularis lives attached to a float made either of natural flotsam or of a cement it secretes itself, which has a texture like that of expanded polystyrene foam.

Among the floats used by adult buoy barnacles are pellets of tar,[5] seaweeds,[2][6] plastic debris,[6] driftwood,[6] feathers,[2][3] cranberries,[2] cuttlefish bone,[2] the "by-the-wind-sailor" Velella velella, seagrass leaves,[3] Styrofoam,[5] seeds,[5] and even apples;[2] they have even been known to colonise the backs of turtles[7] and the sea snake Pelamis platurus.

[9] D. fascicularis appears to be increasing in abundance as a result of anthropogenic marine debris accumulating in the sea;[5] this source of floats was of "minor importance" in 1974.

Dosima is distinguished from Lepas by the form of the carina, and by the exceptional thinness and brittleness of its exoskeleton.

[10] D. fascicularis has a cosmopolitan distribution, with a preference for temperate seas,[11] having been found at latitudes from 71° North off Siberia to 57° South near Cape Horn.