Since Cairns has no city beaches, most people head right out to the reef to swim and snorkel. North of the airport, the neighborhood beach communities of Machans Beach, Holloways Beach, Yorkey's Knob, Trinity Beach, and Clifton Beach are prime for swimming from June through September. It's crucial to avoid the water at other times, however, when deadly box jellyfish (marine stingers) and invisible-to-the-eye Irukandji jellyfish float in the water along the coast.