We report, for the first time to the best of our knowledge, a watt level cw fiber laser at $\sim 2\mathrm{\mu m}$ from a piece of 40-cm-long newly developed highly thulium-doped ( $3.76\times {10}^{20}\text{ions}/{\mathrm{cm}}^3$ ) tungsten tellurite glass double cladding fiber pumped by a commercial $800\mathrm{nm}$ laser diode. The maximum output power of the fiber laser reaches $1.12\mathrm{W}$ . The slope efficiency and the optical–optical efficiency with respect to the absorbed pump are 20% and 16%, respectively. The lasing threshold is $1.46\mathrm{W}$ , and the lasing wavelength is centered at $1937\mathrm{nm}$ .