Thesea is een geslacht van neteldieren uit de klasse van de Anthozoa (bloemdieren).
Soorten Thesea alternata Nutting, 1910 Thesea antiope Bayer, 1959 Thesea bebrycoides Nutting, 1910 Thesea bicolor Deichmann, 1936 Thesea boninensis Aurivillius, 1931 Thesea campanulifera Nutting, 1910 Thesea citrina Deichmann, 1936 Thesea crosslandi Hickson, 1928 Thesea dendritica (Nutting, 1910) Thesea filigella (Thomson & Dean, 1931) Thesea flava Nutting, 1910 Thesea flexilis Nutting, 1910 Thesea gracilis (Gray, 1868) Thesea grandiflora Deichmann, 1936 Thesea granulosa Deichmann, 1936 Thesea guadalupensis (Duchassaing & Michelotti, 1860) Thesea hebes Deichmann, 1936 Thesea immersa Nutting, 1910 Thesea mitsukurii (Kinoshita, 1909) Thesea nivea Deichmann, 1936 Thesea nutans Duchassaing & Michelotti, 1864 Thesea pallida Nutting, 1910 Thesea parviflora Deichmann, 1936 Thesea plana Deichmann, 1936 Thesea pulchra Nutting Thesea reticuloides Nutting Thesea rigida (Thomson, 1927) Thesea rubra Deichmann, 1936 Thesea rugosa Deichmann, 1936 Thesea solitaria (Pourtalès, 1868) Thesea talismani Grasshoff, 1986