http://www.johnkerry.com/communities/veterans/service.html
December 6, 1968 Kerry moved to Coastal Division 11 at An Thoi on Phu Quoc Island
December 13, 1968 Kerry moved to Coastal Division 13, Cam Ranh Bay
December 24, 1968 Kerry involved in combat during the Christmas Eve truce of 1968. The truce was three minutes old when mortar fire exploded around Lieutenant Kerry and his five-man crew. Reacting swiftly, John Kerry and his crew silenced the machine gun nest
January 22, 1969 Kerry and other Swift boat commanders travel to Saigon for meeting with Adm. Elmo Zumwalt, Commander Naval Forces Vietnam (COMNAVFORV), and Gen. Creighton Abrams, Commander United States Military Assistance Command Vietnam (COMUSMACV
Kerry confirms on his website that he was stationed in Cam Ranh Bay during the time in question. The Bay is in the lower right hand corner of the map in the delta looking area directly above the word "South". Cambodia is along ways from there.