Adjacent to Wat Phromviharn and near the large temple, lies an old temple outside the city walls of Phetchaburi. This temple, Wat Trailok, was established during the Ayutthaya period in 1884. The existence of Wat Trailok dates back to the Ayutthaya era, as documented by a notable figure in Phetchaburi's history, Phaya Mahathalwan Pratehos (Kae Thalwan Na), who was the governor of Phetchaburi during the late reign of King Rama III. The temple spans approximately 5 rai, 3 ngan, and 80 square wah, and serves as a place of worship for monks of the Mahayana tradition.