Google Cloud Platform for Developers

Datastore locations

Datastore may be configured to run in either regional or multi-regional locations. A regional location allows for lower write latency than multi-regional locations. Because there are more options on where to run regional configurations, this option also allows for better collocation of data with other Google Cloud services, or with a geographically concentrated user base.

Note, however, that for a normal distribution of users, multi-region locations will provide a better overall read latency:

The Datastore location may be regional or multi-regional, with locations across the globe

Both regional and multi-regional configurations ...