Microplastics are an emerging and highly concerning topic in the field of marine pollution. Micro- and mesoplastics are known to be ingested by a variety of marine organisms and can cause a host of physiochemical and indirect damages to organisms. The ingestion of plastics by sea turtles is a well-documented phenomenon; however, little is known regarding internal exposure time or effects in sea turtles. We experimentally dosed 21 post-hatchling green turtles, via feed, with a preselected size range of irregularly shaped micro- and mesoplastics and monitored the passage through the gut in a time series. The gastrointestinal (GI) tract was excised into five functionally unique sections and inspected. Recovery of plastics within each section was quantified based on count and size. Turtles were found to actively consume plastics which do not resemble natural food items presenting grave concerns for conservation efforts. Plastic particles were found to travel through the GI tract in large groups and occasionally formed aggregates of plastics and faecal matter in the latter sections of the colon. Smaller particles passed faster through the tract, likely due to reduced mass and decreased chance of inhibition by passage diameter. Future gut passage studies are recommended to identify maximum retention time and conduct a census of microplastic load in wild post-hatchling turtles to gain a comprehensive understanding of the threat of micro- and mesoplastics to turtles in the pelagic environment.