"Close to home in Slovakia, knows guys on the team and has played in Prague before so he is comfortable there," his agent Matt Keator said via email.
The 35-year-old Chara also played in Prague for HC Sparta as a junior player in 1995-96. He finished last season with a career-high 52 points after helping the Bruins win the Stanley Cup in 2010-11 with a 44-point campaign.
Bruins assistant captain Patrice Bergeron will play in Switzerland for HC Lugano during the lockout.
Bergeron is leaving Thursday to join his new team.
"I know it's a great league, fast pace, high tempo and a great country," Bergeron said via text message to ESPNBoston.com. "The overall situation seemed perfect for me to go work on my game and try to help Lugano as much as I can."
Chara and Bergeron become the eighth and ninth Bruins players to join a foreign team for the lockout, joining Tyler Seguin (Switzerland), Dennis Seidenberg (Germany), Tuukka Rask, David Krejci and Andrew Ference (Czech Republic), Anton Khudobin (Russia) and Rich Peverley (Finland).
Bruins forward Shawn Thornton was still weighing his options as of last week.
Information from ESPNBoston.com's Joe McDonald and James Murphy was used in this report.