We report continuous-wave laser operation with Yb(15 at .%):Ca4YO(BO3)3 (Yb:YCOB) reaching 26 W of output power in the thin disk laser setup at an optical-to-optical efficiency of 58% and a slope efficiency of 67% in the 𝐄∥𝐙 polarization. In the 𝐄∥𝐗 polarization the efficiency of the laser was slightly lower, but a large tuning range of 95 nm with several watts of output power could be obtained here. Furthermore, applying the pinhole method, the fluorescence lifetime was determined to be 2.2 ms. The obtained results reveal that Yb:YCOB is a promising candidate for the generation of very short pulses at high pulse energies in the thin disk laser setup.