The long-term fate of plastics in the ocean and their interactions with marine microorganisms remain poorly understood. In particular, the role of sinking plastic particles as a transport vector for surface microbes towards the deep sea has not been investigated. Here, we present the first data on the composition of microbial communities on floating and suspended plastic particles recovered from the surface to the bathypelagic water column (0-2000 m water depth) of the North Pacific Subtropical Gyre. Microbial community composition of suspended plastic particles differed from that of plastic particles afloat at the sea surface. However, in both compartments, a diversity of hydrocarbon-degrading bacteria was identified. These findings indicate that microbial community members initially present on floating plastics are quickly replaced by microorganisms acquired from deeper water layers, thus suggesting a limited efficiency of sinking plastic particles to vertically transport microorganisms in the North Pacific Subtropical Gyre. Display omitted •Differential microbial communities on floating versus submerged plastic particles in the North Pacific Subtropical Gyre•Plastic sinking from surface waters towards the underlying deep sea provides only a limited transport for surface microbial communities•Hydrocarbon-degrading bacteria colonize plastic particles in surface and subsurface waters•Subsurface plastic particles harbor a more specialized microbial community than plastic particles afloat at the sea surface