Abstract For the realization of a sufficient fuel cycle in a fusion reactor, tritium permeation barriers have been studied mainly using ceramics coatings to suppress tritium leakage through structural materials. In this study, the first trial of fabrication and characterization of yttria-stabilized zirconia (YSZ) coatings has been carried out. The YSZ coatings containing 4 mol% Y2O3 were deposited on reduced activation ferritic/martensitic steels by radio-frequency magnetron sputtering devices in two different deposition modes. The coating fabricated in the metallic mode showed a lower density with many cracks, and deteriorated after annealing and deuterium permeation tests at 600 °C. On the other hand, the coating fabricated in the poison mode showed relatively higher density, and did not deteriorate from the result of the deuterium permeation measurements at up to 600 °C. These results suggest that the YSZ coating deposited in the poison mode would be applied as a tritium permeation barrier.