James Shears was born in Exeter, Devon and was discharged from H.M.S. Salvador del Mundo as an Ordinary Seaman to H.M.S. Royal Sovereign on 17 July 1803, aged 32, and served aboard that ship at the Battle of Trafalgar.
Shears was discharged to H.M.S. Formidable on 20 December 1805, and subsequently served aboard H.M.S. Ardent from 8 Apr 1811, and H.M.S. Asia from 18 Feb 1812 until 1 June 1815, when he was discharged ‘from the service’, aged 45 years.