We took a boating tour of the lake and it was amazing. The best leisure boating I ever took in my life.
There are many boat jettys around Vembanad lake from where you can do the tour, we took the tour from "Kavanattinkara" boat jetty. It was a small boat and takes you through the lake and then most importantly through the canals.
The canals offer much better views, they are filled with watermosses and lotuses that were on their blooming period while we were visiting. There were many different species of birds, some with neon colors, there were schools of ducks floating around and then you can also see the locals going on with their daily lives.
Throughout the tour you will be able to see hundreds of hoiseboats, some small and some very very large floating around carrying the visitors. You can also book one of them and stay in them for one or two days while it takes you to many different places around the lake to have great experiences. For us, we were very content with the small boat tour that finished in three and half hours.