Mammals:
* Platypus: A unique monotreme, the platypus is semi-aquatic, spending much of its time in rivers and streams. It has webbed feet, a flat bill, and a dense fur coat for insulation in water.
* Echidna: There are several species of echidna in Australia, and some are semi-aquatic. The short-beaked echidna, for example, can swim and forage for food in water.
* Water Rats: Several species of water rats, including the rakali and the swamp rat, are semi-aquatic, living near water bodies and spending significant time in or near water.
Birds:
* Ducks: Australia has several duck species, including the Australian wood duck, the black duck, and the Pacific black duck, which are all semi-aquatic.
* Grebes: Grebes are diving birds, and several species, like the Australian grebe, are found in Australia's lakes and waterways.
* Herons and Egrets: Various heron and egret species, such as the white-faced heron and the pied heron, are semi-aquatic, foraging for food in wetlands and shallow water.
Reptiles:
* Freshwater Crocodiles: Although not strictly semi-aquatic, freshwater crocodiles are largely aquatic, inhabiting rivers, lakes, and wetlands. They are skilled swimmers and spend much of their time submerged.
* Snakes: Some snake species, like the water python and the brown tree snake, are semi-aquatic, adapting to life near water and capable of swimming.
* Lizards: Certain lizard species, like the water skink and the eastern water dragon, are semi-aquatic, spending time in and around water bodies.
Amphibians:
* Frogs: Many frog species in Australia are semi-aquatic, spending part of their life cycle in water (for tadpole stage) and part on land.
* Salamanders: Some salamander species in Australia are also semi-aquatic, spending time in damp environments near water.
This list is not exhaustive, as there are many other semi-aquatic animals found in Australia. The specific types of animals found in a particular area depend on the local environment and habitat.