Design of a distributed coupling toolkit for high performance computing environment. Computer simulations become more realistic as they include interactions between different physical phenomena. Here, we focus on the design of a flexible, scalable and distributed coupling library for High Performance Computing applications, the Distributed Coupling Toolkit (DCT), compare it with other coupling approaches and report some preliminary results. The work presented here is part of a larger effort to couple models, like the General Curvilinear Coastal Ocean Model, inside the General Curvilinear Environmental Model.