Porous ceramics find applications in a diversity of technological fields ranging from catalysis, sensors, biomedicine, energy conversion, and photonics. In many of these applications, the interfaces, including the structures’ surfaces, and their interaction with the surrounding environment are a key aspect to their performance. In this talk, I will demonstrate the power of atomic layer deposition (ALD) for the fabrication and functionalization of 3D porous structures. I will also show that ALD can precisely introduce dopants or second phases, concomitantly with spatial (nano)structuring altering the cellular ceramics’ phases and thermal stability. The focus will be on oxide-based ceramics and I will present examples of porous structures made out of or functionalized with SiO2, Al2O3, ZrO2, TiO2 or mullite (ALD supercycling), where the enhancement of thermal stability, phase stabilization and suppression of grain growth is achieved. The combination of “traditional” material selection with ALD nanostructuring leads to highly-stable porous structures for applications such as catalysis, photonics and colorimetric sensors.