"Barb" resumed a normal training schedule in the Hawaiian operating area through the first four months of 1967. Soon thereafter, however, her routine underwent a significant change when she embarked on her first deployment to the Far East on 9 May. She arrived at Naha, Okinawa, on 22 May, and sailed for Vietnamese waters on the 27th for a Vietnam War tour of duty with Task Group 77.9. After that assignment, "Barb" made a liberty call at Singapore before heading for Yokosuka on 19 June. The submarine spent nine days at Yokosuka and then returned to sea for almost three weeks of unspecified operations. Another upkeep period back at Yokosuka closed out the month of August, at which point "Barb" got underway for Hong Kong and a week-long liberty and goodwill visit. While on her way back to the Vietnamese war zone, she received orders diverting her to training duty at Naha, Okinawa. That employment lasted until the second week in October, at which time she headed for Guam. Though diverted briefly to Subic Bay, "Barb" reached her destination on 15 October. At the conclusion of some tactical exercises and upkeep at Guam, she set out on the voyage back to Hawaii on 24 October. The submarine ended her first Far Eastern deployment when she reentered Pearl Harbor on 1 November.