Jyothikumaran of Kollam, a businessman in Dubai, had sought the court's permission to go abroad after a Kollam court turned down his plea.
The high court had on May 30 granted bail to the two marines -- Latore Massimilianio and Salvatore Girone -- on various conditions including the one that the two sureties should not leave the country without the court's permission.
Relaxing the condition, Justice N K Balakrishnan permitted Jyothikumaran to go abroad till September 28.
The two marines were arrested from Italian merchant vessel Enrica Lexie on February 19 after they allegedly shot dead the fishermen off Kerala coast. They were released on bail on June 2.