Session Description: The National Ecological Observatory Network (NEON) collects and provides open ecological data from over 80 locations across the United States to better understand how U.S. ecosystems are changing. NEON data cover a wide range of subject areas within ecology, including organismal observations, biogeochemistry, remote sensing, and micrometeorology. Some datasets already span several years of data collection. This workshop will provide an introduction to discovering, accessing and preparing plant phenology observation data, primarily using R. The workshop will be divided into three sections of roughly equal length. The first section will feature an introductory presentation highlighting NEON educational resources for accessing and working with NEON data, an overview of the NEON phenology data collection protocol, and an introduction to the NEON data portal. The second section will include a code-along guide to (a) accessing data through the NEON API from an R environment using the neonUtilities and geoNEON R packages, (b) understanding the contents and quality of various data packages, and (c) performing common data merges, visualizations, summarizations, and transformations with NEON plant phenology data. In the last section, we will discuss available datasets that are relevant to NEON phenology data, including meteorological data from the NEON towers and data hosted by external partners (e.g. The PhenoCam Network and USA National Phenology Network). Basic familiarity with R is required for participation in the workshop.