Cross-cloud is a strategy followed by organisations to use servicesprovided by multiple cloud service providers. To provide a seamlessexperience, IAM interoperability issues need to be addressed. Current approachesinvolve relying on a third party cloud broker which causes knownproblemsthat originally led to the concept of cross-cloud. In this article, weanalyze the IAM interoperability issues when building a cross-cloud environmenton top of the current major cloud service providers (Amazon WebService, Microsoft Azure and Google Cloud Platform) by implementing across-cloud storage application. This experiment demonstrates the need tointegrate new identity management systems to cloud IAM services in thefuture. We then propose a cross-cloud identity management model thatfollows the Self-Sovereign Identities principles and which is interoperablewith existing cloud IAM services.