American lobsters (Homarus americanus) are native to the east coast of North American and Canada, but have been imported live into Europe for several decades resulting in their escape into the wild. American lobsters have the potential to have a significant impact on the European lobster (Homarus gammarus) fisheries in Europe, but the status of American lobsters is not well understood, especially in Great Britain (GB) where reports have been sporadic. Reports were collated from across GB of American lobsters being caught in coastal waters. Between 1988 and 2011, 26 individuals have been positively identified using standard taxonomic techniques. American lobsters were found predominantly in waters off southern England, with no confirmed reports from Wales and a single report from Scotland. However, there are anecdotal reports of American lobsters being found in much greater numbers from around GB. The potential threat that American lobsters pose to fisheries in GB and the rest of Europe is discussed along with recommendations to better estimate the numbers of animals being released.