In this letter, authors have proposed a circular structured photonic crystal fiber for low-loss terahertz waveguiding. Transmission characteristics of the photonic crystal fiber (PCF) have been conducted by implementing a perfectly matched layer (PML) in the boundary using finite element method. Power transmitted through the core has been improved by tuning the geometries of the core air holes. The proposed design at the porosity of 80% and a diameter of 304 µm has reported a very low effective material loss of 0.046 cm⁻¹. In the meantime, it reduces the maximum bulk absorption material loss by ∼77%. Moreover, the utmost birefringence of 0.057 is derived at the frequency f = 1.01 THz. Properties like, power fraction of the core air holes, responses of the effective material loss on the basis of the geometric parameter, power fraction with respect to diameter, have been also reported and well discussed.