The data included in this data package were collected in the lagoon of Moorea, French Polynesia. Data on coral mortality were collected in July 2019. Data on nitrogen content (%N) in the long-lived brown macroalga Turbinaria ornata were collected during six sampling campaigns between January 2016 and May 2021 to characterize nitrogen availability at each site. Data on seawater temperatures at six LTER sites in the back reef were collected from 2005-2019, but temperature loggers at two sites (LTER 1 and LTER 6) only recorded partial ocean temperature records during the heatwave from 2018-2019. We used our entire time series (spanning from 2005 to 2018) of temperature across our four long-term sites for which we have data in 2019 to predict ocean temperature data for LTER 1 and LTER 6 in 2019. These data were used for analyses in the manuscript entitled "Effects of nitrogen enrichment on coral mortality depend on the intensity of heat stress". This material uses data collected by the U.S. National Science Foundation's (NSF) Moorea Coral Reef Long Term Ecological Research (MCR LTER) site under Grant No. OCE 2224354 (and earlier awards). Additional financial support to the MCR LTER site was provided through a generous gift from the Gordon and Betty Moore Foundation. Research was completed under permits issued by the French Polynesian Government (Délégation à la Recherche) and the Haut-commissariat de la République en Polynésie Francaise (DTRT) (Protocole d'Accueil 2005-2024).