A: It is safe to swim all year round in Cairns, Port Douglas and the Great Barrier Reef but it is highly recommended that you wear a lycra suit when entering the water in the warmer months of November-April.

In 2026, you can technically swim all year round in Cairns because the tropical water temperature remains a warm 23°C to 29°C (73°F–84°F). However, the where and how you swim changes significantly based on the season. During the "Stinger Season" (November to May), the coastal waters are inhabited by dangerous Box Jellyfish and Irukandji. During these months, you should only swim in the ocean within "Stinger Nets" at designated beaches (like Palm Cove) or wear a full-body lycra "stinger suit." A safer and very popular year-round option is the Cairns Esplanade Lagoon, a massive, saltwater swimming pool that is free of jellyfish and crocodiles. For ocean lovers, the Great Barrier Reef itself is generally safe for swimming year-round because the jellyfish are less common in the deep, offshore waters, though most tour operators still provide stinger suits during the summer months for added safety. While the "winter" months (June to August) are the most comfortable for tourists due to lower humidity and no jellyfish risk, Cairns remains a premier year-round aquatic destination for those who follow the local safety signs.