We investigated key physiological tolerances of the invasive euterrestrial talitrid amphipod (or landhopper) Arcitalitrus dorrieni; desiccation, salt, high and low temperatures. The critical relative humidity below which, A. dorrieni experiences desiccation stress is very high (95–100%), making it completely reliant on the leaflitter/soil microhabitat. It is tolerant of a wide range of (sea) salt concentrations (5–750 mOsmol l −1) but is extremely vulnerable below 5 mOsmol l −1. A. dorrieni does not tolerate low temperatures with a mean lower limit of 1.4 °C, but with no individual surviving <0 °C. The range of upper thermal tolerance (30–37.3 °C) was similar to that found for other landhopper and beachflea species. Based on its tolerance to these environmental factors it is suggested that A. dorrieni has a limited potential to invade further into Britain, being restricted to areas with sufficiently high ion concentrations and mild winters.