Amphibians can be found on all continents around the world except Antarctica . Their habitat ranges from sea level, in caves that is lower than the sea level, underground streams without lights, to the peaks of mountain ranges. No amphibians can adapt to life in sea water, therefore, they generally cannot be found on sea islands.

The distribution of the species, the genus, and the family of amphibians (biological geography) varies significantly between different groups due to the environmental conditions in the geology of the distant past (biogeographic history), recent past, and modern time (ecological biogeography). The biogeographic history allows us to learn the distribution that was hard to explain, for example, caecilian can be found in isolated Seychelle Islands in the middle of the Indian Ocean – approximately 1000 km ( 620 mi ) to the north east of Madagascar is because these islands were the remnants of Indian Plate when it broke away from African continent during the Mesozoic Period.

A more recent example is the explanation for the low diversity of Plethodontidae (2 genera, and 25 species) in South America, while those in North America have its distribution center, and have exhibited relatively high diversity (13 genera and 177 species) in Central America also. During the Eocene Epoch – the formation of the Panama Portal from the erosion and continental drift that disconnected the South America from Central America , and the two populations did not re-link in the next 500 million years thereafter due to the lack of volcanic activity and associated uplift effect. The gap was not restored until approximately 3 million years ago and the distribution of salamanders into South America was re-established.

The distribution of other amphibians can be explained through their physiological capabilities and residing in physical and biological environments. For example, no amphibians are found living in the ocean because they will be unable to maintain osmotic equilibrium in sea water leading to continuing loss of water, dehydration and finally, death. Some salamanders and frogs may withstand high levels of salt, but only one species is observed – the Fejervarya cancrivora of Southeast Asia . By maintaining a high level of blood urea concentration, they are able to maintain osmotic balance with the environment, which allows them to inhabit the mangroves in estuaries under alkalinic condition.

Many frogs and salamanders dwell at locations with high-latitude or high-altitude with freezing temperatures that pose a possible threat to their survival. At temperatures below freezing, they must either enter hibernation or wait until the temperature climbs above the freezing point before returning to a breeding pond; in reality, some species are resistant to freezing which allowed them to be distributed in areas that are difficult for other amphibians to survive. Some species of amphibians (frogs or salamanders) may release glucose or glycogen into the blood stream to reduce the freezing point of the water in the cells to be able to survive at freezing temperatures. Not surprisingly, Rana sylvatica and Pseudacris crucifer are the two earliest species that entered the breeding ponds of North America using glucose as an anti-freeze.

Fire is one of the environmental factors that limit the distribution of amphibians. Many fires occur in habitats. Bush fires take place in coastal regions of California frequently, but Californian salamanders are able to survive by secreting mucus rapidly and directly cross the flames. Many salamanders were observed to dash through flames when the viscosity of the mucus reaches the similar consistency to meringue (whipped egg white); the white shell can be shed easily from the moist body after passing through the flames. Fire is a common phenomenon in the Savanna of Eastern Africa; a recent study has shown that reed frogs react to crackling sound as the fire approaches, and would hide under protective shelters; and therefore are able to survive in these inhabitable surroundings.