The water-soldier is native to England and in Europe - south to Spain, Italy, Bulgaria and European Turkey and north to Finland and east to Siberia.
In the British Isles it is now extinct in the Cambridgeshire fens and has largely disappeared from Lincolnshire and Yorkshire.
The greatest concentration of surviving S. aloides sites regarded as native in England is in East Norfolk. Its native status in the rest of Great Britain is uncertain.
It also occurs in large numbers in Co. Fermanagh, Northern Ireland where its native status is debatable.
Stratiotes aloides is found mainly in sheltered bays of larger lakes, backwater ponds, ditches and canals.
In Co. Fermanagh, Northern Ireland, it occurs in natural shallow lakes and ditches and in England S. aloides was formerly found in lakes and slow moving rivers, but now is confined to ditches of grazing marshes in East Norfolk.