Study of plastic marine debris (PMD) has revealed widespread distribution of plastics within the ocean, and investigated how PMD influences marine ecosystems. However, few studies have investigated microorganismal interactions with PMD. I addressed this gap by studying the development and structure of PMD colonizing microbial communities. Plastic resin samples including polyethylene, polypropylene, polystyrene and a glass control were submerged in the waters of Woods Hole, MA and sampled from 1 week to 6 months after immersion. Microbial community structure was analyzed over time with scanning electron microscopy (SEM) and next generation sequencing of the 16S rRNA sequence. Next generation sequencing provided comprehensive taxonomic data allowing analysis of community structure over time. Analysis of Bray-Curtis dissimilarity values and community membership over time showed the glass and plastic colonizing communities were largely similar in structure. SEM micrographs allowed the calculation of diatom abundance and observation of ecological interactions. 16S and SEM data both reported patterns in community development of initial autotroph dominance followed by a decline and replacement by heterotrophic groups. These results enhance our understanding of the succession and community structure of PMD colonizing microorganisms.