Data on the type, provenance, quantity (density), and rate of accumulation of beach-washed plastic debris were recorded on Henderson Island, a remote, uninhabited island in the South Pacific during 29 May – 15 August 2015. Henderson Island is rarely visited by humans, thus debris on the islands' beaches may act as a proxy for the adjacent South Pacific Ocean. The island was found to contain the highest density of debris anywhere in the world, up to 671.6 items/m2 (mean ± SD: 239.4 ± 347.3 items/m2 on the surface of the beaches. Approximately 68% of debris (up to 4,496.9 pieces/m2) was buried <10 cm in the beach sediment. Up to 26.8 new items/m are thought to accumulate daily.

Latex balloons act like plastic in the ocean: they can travel far from their point of origin on atmospheric and water currents and float at the sea surface where they can be eaten by wildlife that mistake it for food. This study quantified the degradation behaviours of latex balloons in saltwater, freshwater, and industrial compost windrows over 16 weeks. The degradation of latex balloons was quantified with bi-weekly measurements of 1) changes in mass; 2) ultimate tensile strength; and 3) changes in surficial composition of balloons via attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). This study tested whether degradation differed between two balloon colours (blue and white) and whether degradation differed between balloons whose packaging labels included the word "biodegradable" and balloons whose packaging did not contain the word "biodegradable", and were thus labeled as "traditional" balloons. Thus, these data consist of 1) mass measurements; 2) load-extension data used to determine ultimate tensile strength; and 3) ATR-FTIR spectra of latex balloons across the variables balloon type (biodegradable; traditional), colour (blue; white), and week sampled (0-16 weeks). Also included are measurements of balloons that did not undergo treatments and are either straight out of the package ("new") or balloons that were inflated but did not undergo any treatments ("inflated").