The 34-year-old debuted in the tournament last year but played just two matches for St. Lucia Zouks after arriving late due to his English County commitments, reports CMC.
"Being involved in CPL 2014 was a fantastic experience and I thoroughly enjoyed playing for the St. Lucia Zouks, albeit briefly," said Pietersen.
"This year I will be available for the duration of the tournament so I hope to be able to make a bigger impact and give the Zouks fans something to shout about.
"The CPL is a very special event and I can't wait to get back out there to experience more of the biggest party in sport."
Pietersen's late arrival had a big impact on the Zouks, and they won just two for their nine matches during the tournament.
The South Africa-born Pietersen, a former England captain, played 104 Tests and gathered 8,181 runs at an average of 47, to be fifth on the all-time list of England run-scorers.
He averaged 40 from 136 One-Day Internationals and nearly 38 from 37 Twenty20s, with a strike rate of 141.