Type species – Oniscus thoracicus Montagu, 1808, by monotypy.
Included species – Ione cornuta Bate, 1863 (eastern north Atlantic); Ione ovata Shiino, 1964 (eastern south Pacific); Ione sarahae n. sp. (eastern tropical Pacific); Ione taiwanensis Markham, 1995 (western tropical Pacific); Ione thompsoni Richardson, 1904 (western north Atlantic); Ione thoracica (Montagu, 1808) (eastern north Atlantic); Ione tubulata Bourdon, 1976 (Indian Ocean).