How can I connect my SAP RISE account to an existing AWS account?

To connect an AWS SAP RISE account to an existing AWS account (I.e. your company account) you can use an AWS VPC Peering (https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html) or an AWS Transit Gateway (http://docs.aws.amazon.com/vpc/latest/tgw/what-is-transit-gateway.html). Both AWS solutions are supported by the SAP RISE offer. For more information please see the How to connect SAP solutions running on AWS with AWS accounts and services (https://aws.amazon.com/blogs/awsforsap/how-to-connect-sap-solutions-running-on-aws-with-aws-accounts-and-services/) blog

NOTE: This answer is provided by the SAP on AWS speciality team and is accurate at the time of publish. Please check comments as the answer may have changed/services evolved.