Abstract: A modular hydrodynamic subsea vehicle comprises an upper section and a lower section, where the upper section comprises a first upper primary module, a second upper primary module operatively connected to the first upper primary module, and, optionally, one or more intermediate upper modules disposed in-between the first and second upper primary modules. The lower section is operatively connected to the upper section and comprises a first lower module, a second lower module operatively connected to the first lower primary module, and, optionally, one or more intermediate lower modules disposed in-between the first and second lower primary modules. The modules are capable of performing a desired set of functionality subsea.