Anion exchange membrane water electrolyzer (AEMWE) is a potentially cost-effective technology for green hydrogen production. Although the normal current densities of AEMWEs are below 3 A ⋅ cm−2, operating them at higher current densities represents an efficient, but little-explored approach to decrease the total cost of hydrogen production. We show here that a benchmark AEMWE has an operational lifetime of only seconds at an ultrahigh current density of 10 A ⋅ cm−2. By using a more conductive and robust AEM, and judicious choices of ionomers, catalyst, and porous transport layer, we have developed AEMWEs that stably operate at 10 A ⋅ cm−2 with extended lifetimes. The optimized AEMWE has an operational lifetime of more than 800 hours, a 5-order magnetite improvement over the current benchmark. The cell voltage is only 2.3 V at 10 A ⋅ cm−2, comparable to those of the state-of-the-art devices operating at current densities lower than 3 A ⋅ cm−2. This work demonstrates the potential of ultrahigh current density AEMWEs.