Abstract: The availability of reconfigurable technologies has enabled the construction of flexible systems allowing run-time reconfiguration of system hardware and software functions. "Seamless communications" (also known in radio communications world as "reconfigurable" or "software-defined" radio) is one of the areas where technologies allowing run-time reconfiguration are highly desirable. This paper presents a new rapid prototyping methodology and platform for prototyping generic seamless communication systems. The methodology combines a C-based software design flow targeting host and DSP processors, and a rapid FPGA hardware design flow based on Handel-C- a C-like programming language. The hardware design flow also supports the generation of partial FPGA configurations. A library of parametrised communication modules was developed to facilitate the rapid construction of common communication architectures. A PC-based prototyping platform provides a set of custom hardware interfaces for prototyping systems with radio-frequency (RF), infra-red (IR) and generic wide-bandwidth communication links. The feasibility of the presented methodology was tested on several simple demonstrator applications.