With 14 goals and three assists, the 29-year-old helped his former club UD Logrones secure a place in the Primera Division RFEF (Spanish third-tier) promotion play-offs.
The 29-year-old remains a key part of Juan Ferrando's plans at the club and is certain to play a vital role not just in the Hero ISL but also in the Mariners' AFC Cup campaign.
Das who hails from West Bengal has made a name for himself in Jamshedpur with impressive performances for Jamshedpur FC last season as he helped himself to four goals and one assist.
The 31-year-old midfielder, who made headlines after scoring the breathtaking winning goal in stoppage time that handed Atletico de Kolkata the ISL title in the inaugural season, will be a valuable addition to the Chennaiyin FC midfield.
The club from western India have further added to their credibility over the last few years by bringing a number of talented youngsters from the state through the ranks while maintaining their eye-catching style of play.