| Cnidarians-Anthozoans | Actinia equina* | 2021 | Definite | Established | Ballast Water, Hull Fouling |
| Algae | Bonnemaisonia hamifera | 2004 | Definite | Established | Hull Fouling |
| Crustaceans-Crabs | Carcinus maenas | 1973 | Definite | Established | Dry Ballast, Hull Fouling, Natural Dispersal |
| Algae | Codium fragile ssp. Fragile | 1966 | Definite | Established | Discarded Bait, Hull Fouling, Natural Dispersal, Oyster Accidental |
| Cnidarians-Anthozoans | Diadumene lineata | 1938 | Definite | Established | Hull Fouling |
| Annelids-Polychaetes | Ficopomatus enigmaticus | 1976 | Definite | Established | Hull Fouling |
| Crustaceans-Crabs | Hemigrapsus sanguineus | 1992 | Definite | Established | Ballast Water, Hull Fouling, Natural Dispersal |
| Crustaceans-Isopods | Ianiropsis serricaudis | 2012 | Definite | Established | Hull Fouling |
| Mollusks-Gastropods | Littorina littorea | 1894 | Definite | Established | Dry Ballast, Hull Fouling, Natural Dispersal |
| Algae | Lomentaria orcadensis* | 1969 | Definite | Established | Hull Fouling |
| Crustaceans-Amphipods | Microdeutopus gryllotalpa | 1968 | Definite | Established | Hull Fouling, Natural Dispersal |
| Cnidarians-Hydrozoans | Moerisia lyonsi | 2014 | Definite | Established | None |
| Protozoans | Perkinsus marinus* | 1991 | Definite | Established | Oyster Accidental |
| Arthropoda-Insects | Telmatogeton japonicus* | 1974 | Definite | Established | Cargo, Hull Fouling |
| Mollusks-Bivalves | Teredo navalis | 1921 | Definite | Established | Hull Fouling |