The data provided here are from a number of sea temperature monitoring programs conducted in tropical and subtropical coral reefs environments around Australia. Data are available from approximately 80 GBR sites, 16 Coral Sea sites, 7 sites in North West Western Australia (WA), 8 Queensland regional ports, 13 sites in the Solitary Islands, 4 sites in PNG and 10 sites in the Cocos (Keeling) Islands. Data are obtained from in-situ data loggers deployed on the reef. Data loggers instantaneously record sea temperatures every 30 minutes and are exchanged and downloaded approximately every 12 months. Temperature loggers on the reef-flat are generally placed just below Lowest Astronomical Tide level. Reef-slope (or where specified as Upper reef-slope) generally refers to depths 5 - 9 m while Deep reef-slope refers to depths of ~20 m.