We present the kinetic energy spectra and fluxes of currents observed from multiple platforms off the U. S. West Coast -- satellite altimeter (ALT), high-frequency radar (HFR), and shipboard acoustic Doppler current profilers (ADCPs). The one-dimensional wavenumber-domain kinetic energy spectra of the HFR-derived surface currents agree with those of the ALT-derived geostrophic currents at scales larger than 100 km, and decay with $k^{-2}$ and $k^{-3}$ at high wavenumber (below 100 km) up to the wavenumber of 0.5 $\mathrm{km}^{-1}$. Moreover, the kinetic energy spectra of subsurface currents obtained from shipboard ADCPs support a continuous transition of energy between mesoscale and submesoscale. A comparison of the kinetic energy fluxes, estimated from the gridded ALT-derived geostrophic currents and submesoscale HFR-derived surface currents, exhibits the potential injection scales of $\it{O}$(100) km and $\it{O}$(10) km, which are consistent with the regional Rossby deformation radius and the dominant length scales of the regional submesoscale eddies, respectively.