In this Northern Territories park, you would think that you were in a documentary about African wildlife (without the elephants and the hippopotamuses). The marshy landscape of the park makes me think of humid Senegalese or Tanzanian plains. The views of Mary River are therefore magnificent but if there was ever a place where you mustn't swim, it would be here.
However, I would recommend that you go on a trip with a guide who will allow you to get up close to crocodiles and numerous rare species. Mary River is the ideal place to observe the birds (jabirus, white-tailed eagles, cranes...) of the wet plains as well as wild buffalo and wallabies. Fishermen are drawn to the region for barramundi fishing (a classic in Australia). The famous spots are Shady Camp and Corroboree Billabong. This last one is truly a sublime part of the park but beware, it is infested with crocodiles.