Karst aquifers may also be transboundary, i.e. crossing political or administrative borders. Typical karst hydrogeology includes a lack of correspondence between the surface and subsurface limits and difficulties in identifying hydraulic boundaries and volumes. A large amount of high-quality drinkable water comes from karst aquifers, with this volume increasing in the future. There is an urgent need to understand karst, and safeguard it and its resources, without being limited by administrative borders. Karst management requires cooperation between the people living on the land, to transfer and disseminate research outcomes, to create awareness of the fragile environment, to build resilience and readiness to cope with natural hazards and the changes they cause, and to minimise disturbance.