NMDC Field Notes is an app microbiome researchers can use to record metadata about the biosamples they collect while they are working in the field. It is a mobile alternative to the browser-based NMDC Submission Portal web app, designed specifically to streamline the process of documenting metadata at the time of biosample collection. Its features (all of which were designed in collaboration with microbiome researchers) include: ORCID login, entry of study and biosample metadata, one-tap entry of user information, geographical coordinates, and dates, user interface forms that are dynamically generated from a LinkML schema, and automatic syncing of study and biosamples metadata with the NMDC Submission Portal.