Coast Guard is a side mission in Infamous 2.
The mission starts when a civilian approaches Cole and tells him that gunboats have pulled up to the shore and are massacring people. Cole must then make his way to the harbor and battle the Militiamen on their gunboats. The mission is complete when Cole defeats all of the Militiamen and all of their boats are sunk.
Upon completion, Cole receives 100 XP and slightly reduces enemy activity in New Marais.