This dataset contains air and water temperature data recorded at multiple shoreline sites on five islands within Boston Harbor, MA USA over the period April - August, 2023. This data was collected using Onset HOBO U-22 temperature loggers that were deployed across 5 islands: Gallops, Georges, Lovell, Peddocks, and Thompson Island. The dataset contains the island name, site designation, date, and time for the temperature data recorded.