Pyrodinium bahamense is a meroplanktonic dinoflagellate that produces paralytic shellfish toxins that cause human poisoning along tropical and subtropical coasts. Cyst morphology, germination characteristics, and toxicity were investigated using samples from Isla San José in the Gulf of California. Morphology was observed through light and scanning electron microscopy. Germination was tested at different temperature (15°C-35°C) and salinity (15-35) conditions in different culture media (natural seawater, GSe, and f/2). To elucidate toxicity of vegetative cells grown from cyst germination, nine strains were subject to toxin analyses through fluorescence high-performance liquid chromatography. Morphological features and size of cysts generally agree with previous descriptions, particularly morphotypes found in the subtropical North Atlantic, where P. bahamense var. bahamense occurs. Cysts exhibit thermophilic and euryhaline characteristics. Highest germination occurred from 20°C to 35°C with the peak between 25°C and 30°C. Excystment occurred at salinities from 20 to 35. Germination occurred in the three culture media, but was highest in the optimal temperature range in the culture medium that included terrestrial soil extract and selenium. Only one strain exhibited toxicity with high saxitoxin concentration (95 pg STX eq cell -1 ).