Backwater is a body of stagnant water connected to a river. The backwaters of Kerala- meandering inland lakes networked by canals - stretch to over 1900km. Boat across these tranquil stretches are an experience unique to Kerala. Large Kettuvalloms (traditional country crafts over 60ft. in length) have been converted into luxury houseboats for these cruises. Local Malayali people call it Kayals.

Kollam(Quilon), Alappuzha(Alleppey) and Kottayam are the principal backwater towns. And if you are visiting the state in the late August/ early september during ten-days Onam harvest festival, you can watch the spectacle of the backwaters. 
 
The boats cross shallow, palm-fringed lakes studded with Chinese fishing nets, and along narrow, shady canals where coir (coconut fibre), copra and cashews are loaded onto boats. Stops are made at small settlements where people live on carefully cultivated narrow spits of land only a few metres wide, and there's the chance to see traditional boats with huge sails, and prows carved into the shape of dragons.
The backwaters of Kuttanad comes vibrantly alive as the venue for the legendry snake boat races. Otherwise the best season to enjoy this part of the country is from December to February.

Kollam Backwaters
One of the oldest ports of the Malabar coast, Kollam was once the centre of the international trade. North of Thiruvananthapuram, 30% of this historic town is covered by the renowned Ashtamudi Lake. The eight hour boat trip between Kollam and Alappuzha is the longesat & most enchanting experience of Kerala's backwaters.

Alappuzha
Also known as the Venice of the East, Alappuzha is famous for its boat races, houseboat holidays, beaches, marine products and coir industry. A singular characteristic of this land is the region called Kuttanad. The Granary of Kerala, Kuttanad is perhaps the only place in the world were farming is done below sea level.

Kumarakom Backwaters
Just 12km from Kottayam, this unique backwater destination situated on the banks of the Vembanad lake is considered the gateway to the backwaters of Kuttanad. The Kumarakom bird sanctuary is a favourite haunt of migratory birds from across the world which makes it a renowed bird watching center. Kumarakom is also a centre for houseboat cruises.