The South Johnstone River is located in Far North Queensland, Australia, and offers a range of paddling experiences from technical whitewater in its upper reaches to more accessible expedition-style runs downstream. The upper sections of the river feature grade IV+ whitewater, while a fishing trail access point farther downstream opens up approximately 15 kilometers of grade II+ water, making that stretch more suitable for intermediate paddlers and stand-up paddleboarders.

Access and take-out logistics present significant challenges. In recent years, land use along the riverbanks has shifted almost exclusively to banana plantations. Due to the threat of Panama Disease, the majority of potential take-out points in these areas are quarantined, severely limiting egress options. Public access points such as bridges are available but are located considerably farther downstream, requiring paddlers to plan for longer trips than the whitewater section alone might suggest.

The most serious hazard on the South Johnstone River is the high population of saltwater crocodiles. Since hunting protections were introduced in the 1970s, crocodile numbers and range have expanded substantially. This expansion has been further accelerated by a large increase in feral pig populations, which provide crocodiles with a consistent food source. The result is not only greater crocodile numbers but also larger individual animals, and crocodiles are now venturing further upstream into areas they previously did not inhabit. Feral pigs themselves also represent a potential hazard for paddlers accessing the river via bush trails.

The river flows through a remote landscape in tropical Far North Queensland. The combination of its isolation, crocodile presence, quarantine restrictions on access points, and the need to navigate logistics around banana plantation land makes this a serious undertaking requiring thorough preparation. The river is also noted as a fishing destination, with species including sooty grunter, barramundi, and rock flagtail present in its waters, reflecting the river's connection to the broader tropical waterway ecosystem of the region.

Given the crocodile population and the remote nature of the run, solo paddling carries elevated risk. The documented first SUP descent of the river was completed as a solo trip, but that context underscores rather than normalizes the hazards involved.