The Kerala backwaters are a chain of brackish lagoons and lakes lying parallel to the Arabian Sea coast of Kerala. The network includes five large lakes linked by canals, both manmade and natural, fed by 38 rivers, and extending virtually half the length of Kerala state. The backwaters were formed by the action of waves and shore currents creating low barrier islands across the mouths of the many rivers flowing down from the Western Ghats range.

Kerala has over 900 kms of interconnected waterways, rivers, lakes and inlets that make up the Kerala backwaters. In the midst of this beautiful landscape there are a number of towns and cities, which are the starting and end points of backwater cruises.

The backwaters have a unique ecosystem - freshwater from the rivers meets the seawater from the Arabian Sea. In certain areas, such as the Vembanad Kayal, where a barrage has been built near Kumarakom, salt water from the sea is prevented from entering the deep inside, keeping the fresh water intact.

Many unique species of aquatic life including crabs, frogs and mudskippers, water birds such as terns, kingfishers, darters and cormorants, and animals such as otters and turtles live in and alongside the backwaters. Palm trees, pandanus shrubs, various leafy plants and bushes grow alongside the backwaters, providing a green hue to the surrounding landscape.

Vembanad Kayal is the largest of the lakes, covering an area of 200 km², and bordered by Alappuzha (Alleppey), Kottayam, and Ernakulam districts. The port of Kochi (Cochin) is located at the lakes outlet to the Arabian Sea. Alleppey, "Venice of the East", has a large network of canals that meander through the town. Vembanad is India’s longest lake.
The kettuvallams (Kerala houseboats / Riceboats) in the backwaters are one of the prominent tourist attractions in Kerala.

Kuttanad is crisscrossed with waterways that run alongside extensive paddy fields, as well as fields of cassava, banana and yam. A unique feature of Kuttanad is that many of these fields are below sea level and are surrounded by earthen embankments. The crops are grown on the low-lying ground and irrigated with fresh water from canal and waterways connected to Vembanad lake.