In Swampscott, Route 129 follows along King's Beach, above Black Will's Cliff and then along Fisherman's Beach before turning more inland, bypassing the Phillips Point neighborhood before coming close to the ocean once again in the Beach Bluff neighborhood as it enters Marblehead. Once in Marblehead, Route 129 continues along Atlantic Avenue before finally terminating at the corner of Atlantic and Ocean, where it meets the eastern end of Route 114. Atlantic Avenue continues into downtown Marblehead from this point, while Ocean Avenue heads across a short isthmus onto Marblehead Neck.