If you want to own a permanent copy, you can buy or rent the dubbed versions on: YouTube
The Ultimate Guide to Watching The Hobbit Trilogy in Tamil The Hobbit Movies Tamil Dubbed Download
The series consists of three films: An Unexpected Journey (2012), The Desolation of Smaug (2013), and The Battle of the Five Armies (2014). If you want to own a permanent copy,
The most reliable platform for the trilogy in India. You can often find the movies available for streaming or as digital rentals/purchases. Check the Amazon Prime Video store for the "Tamil" audio track option. The Desolation of Smaug (2013)
Most "Tamil dubbed" versions available for download are: