| Species name | Common name | Distribution | Max. Length (cm) |
|---|---|---|---|
| Okenia amoenula (Bergh, 1907) |
Southeast Atlantic and Western Indian Ocean | ||
| Okenia angelensis Lance, 1966 |
Angeles okenia | Eastern Pacific | 1.2 |
| Okenia angelica Gosliner & Bertsch, 2004 |
Angelic okenia | Eastern Central Pacific | 2 |
| Okenia aspersa Alder & Hancock, 1845 |
Northeast Atlantic | ||
| Okenia barnadi Baba, 1937 |
Northwest Pacific | ||
| Okenia brunneomaculata Gosliner, 2004 |
Western Central Pacific | ||
| Okenia cochimi Gosliner & Bertsch, 2004 |
Cochimi's okenia | Eastern Central Pacific | 0.4 |
| Okenia cupella (Vogel & Schultz, 1970) |
Western Atlantic and the Mediterranean | 0.2 | |
| Okenia elegans (Leuckart, 1828) |
Northeast Atlantic and the Mediterranean Sea | ||
| Okenia hiroi (Baba, 1938) |
Hiro's sea slug | Northwest Pacific | |
| Okenia hispanica (Valdés & Ortea, 1995) |
Mediterranean Sea | ||
| Okenia japonica Baba, 1949 |
Western Pacific | ||
| Okenia kendi Gosliner, 2004 |
Western Central Pacific | ||
| Okenia leachii (Alder & Hancock, 1854) |
Northeast Atlantic | ||
| Okenia mediterranea (Von Ihering, 1886) |
Mediterranean Sea | ||
| Okenia mexicorum Gosliner & Bertsch, 2004 |
Ali & Orso's okenia | Eastern Central Pacific | 0.7 |
| Okenia mija Burn, 1967 |
Indo-West Pacific | 2 | |
| Okenia miramarae Ortea & Espinosa, 2000 |
Western Atlantic | 0.5 | |
| Okenia nakamotoensis (Hamatani, 2001) |
Western Central Pacific | ||
| Okenia pilosa (Bouchet & Ortea, 1983) |
Indo-West Pacific | ||
| Okenia plana Baba, 1960 |
Flat okenia | Indo-Pacific | 1 |
| Okenia plebeja (Bergh, 1902) |
Western Pacific | ||
| Okenia purpureolineata Gosliner, 2004 |
Western Central Pacific | ||
| Okenia quadricornis (Montagu, 1815) |
Seasquirt okenia | Western Atlantic and the Arctic | |
| Okenia sapelona Marcus & Marcus, 1967 |
Sapelo okenia | Western Atlantic | 0.76 |
| Okenia vancouverensis (O'Donoghue, 1921) |
Vancouver okenia | Eastern Pacific | 1.8 |