General:
* Pagkakaroon (literally "having")
* Kaka-yarian (literally "capability")
* Pagiging available (literally "being available")
Specific contexts:
* Availability ng produkto (availability of product)
* Availability ng serbisyo (availability of service)
* Availability ng tao (availability of a person)
The best translation will depend on the specific situation. For example, "availability of a product" would be translated as "pagkakaroon ng produkto" or "availability ng produkto".
It's always helpful to provide more context when asking for a translation so the most accurate meaning can be provided.