A single-wavelength Brillouin fiber laser (BFL) is demonstrated at the extended L-band region using bismuth-based erbium-doped fiber (Bi-EDF) for the first time to the best of our knowledge. A $2.15\text{-}\mathrm{m}$ -long Bi-EDF is used to provide both nonlinear and linear gains to generate a stimulated Brillouin scattering (SBS) and to amplify the generated SBS, respectively. The BFL operates at $1613.93\mathrm{nm}$ , which is upshifted by $0.09\mathrm{nm}$ from the Brillouin pump with a peak power of $2\mathrm{dBm}$ and a side-mode suppression ratio of more than $22\mathrm{dB}$ . The generated BFL has a narrow linewidth and many potential applications, such as in optical communication and sensors.