HSwMS Tirfing was the third ship of the John Ericsson-class monitors built for the Royal Swedish Navy in the mid-1860s. She was designed under the supervision of the Swedish-born inventor John Ericsson, and built in Sweden. Tirfing made one foreign visit to Russia (visits to Norway did not count as foreign as that country was in a personal union with Sweden) in 1867, but remained in Swedish or Norwegian waters for the rest of her career. The ship was reconstructed between 1903 and 1905, but generally remained in reserve. She was mobilized during World War I and sold in 1922 for conversion to a barge.