HMS C1 was a British C class submarine built by Vickers, Barrow. She was laid down on 13 November 1905, launched 10 July 1906 and was commissioned on 30 October 1906. C1 was equipped with wireless telegraphy. She was converted to a surface patrol boat and renamed S8 for Adriatic service. On 23 April 1918 she was packed with dynamite to be blown up at Zeebrugge Mole. However, this did not happen. C1 was sold 22 October 1920 to Stanlee, and resold 14 November 1921 to Young, Sunderland.