One Ayala – South Tower is an office development atop One Ayala Mall together and is part of the 3-tower development (The other office towers are called East and West Towers).

It is one of the most accessible offices in the city with direct access to the Ayala MRT station and within the development is the BRT PUV/Bus Terminal.

One Ayala is part of the Ayala Center which is highly commercialized. There is a high concentration of key establishments such as malls and hotels.

This tower is the last one to be completed and is labelled as the HQ type office among the three as it has a smaller floorplate and requires a lower density.