A mid-infrared fiber laser operating at λ≈3 μm is demonstrated using a Ho³⁺/Pr³⁺ co-doped AlF₃-based glass fiber as a gain fiber. Under 1150 nm single-mode fiber laser pumping, the fixed-wavelength laser had maximum output power of 1.02 W, a slope efficiency of 10.7%, and M²≈1.2. The results prove this type of fiber is a potential gain medium for more powerful mid-infrared fiber lasers.