DynamoDB Global Tables

Yes this is possible, we can add another replica in different region once the existing DynamoDB global table created. Have a look on the following requirements

• The table must have the same partition key as all of the other replicas.
• The table must have the same write capacity management settings specified.
• The table must have the same name as all of the other replicas.
• The table must have DynamoDB Streams enabled, with the stream containing both the new and the old images of the item.
• None of the new or existing replica tables in the global table can contain any data.

If global secondary indexes are specified, the following conditions must also be met:

• The global secondary indexes must have the same name.
• The global secondary indexes must have the same partition key and sort key (if present). https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/globaltables_reqs_bestpractices.html?shortFooter=true

Region support for global tables Version 2017.11.29 is limited to US East (N. Virginia), US East (Ohio), US West (N. California), US West (Oregon), Europe (Ireland), Europe (London), Europe (Frankfurt), Asia Pacific (Singapore), Asia Pacific (Sydney), Asia Pacific (Tokyo), and Asia Pacific (Seoul).

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/V2globaltables.tutorial.html