Control of temperature is a major challenge for industrial microalgae production in photobioreactors outdoors. Strains with tolerance for high temperatures can reduce the cost of production as active temperature control is not required. In this study, marine photoautotrophic microorganisms were isolated to reduce the need for control of high temperature. Twenty-two samples were taken from different saline waters on the Caribbean island Bonaire. During strain enrichment, a temperature of 40 °C was used as selective pressure and strains with the highest growth rate were selected. We isolated and identified 59 strains, after which 5 were selected for characterization on growth rate and biomass composition. Picochlorum sp. and Leptolyngbya sp. showed optimal growth at 40 °C and 35 °C with a growth rate of 0.12 h−1 during daytime, respectively. The strains contain 62.1% and 68.2% of protein and have varying fatty acid compositions suitable for application as edible oil and biofuel.