Radio observations offer a dust-independent probe of star formation and active galactic nucleus (AGN) activity, but sufficiently deep data are required to access the crossover luminosity between these processes at high redshift (z > 4.5). We present three spectroscopically confirmed high-redshift radio sources (HzRSs) detected at 1.3 GHz at z = 4.9–5.6, with radio luminosities spanning L1.3 GHz ≈ 2–$5\times 10^{24} \, \rm W \, Hz^{-1}$. These sources were first identified as high-redshift candidates through spectral energy distribution (SED) fitting of archival Hubble, JWST NIRCam+MIRI, and ground-based photometry, and then spectroscopically confirmed via the H α emission line using wide-field slitless spectroscopy from JWST COSMOS-3D. The star formation rates (SFRs) measured from SED fitting, the H α flux, and the 1.3 GHz luminosity, span ~100–$1800\, \rm M_{\odot } \, yr^{-1}$, demonstrating broad agreement between these SFR tracers. We find that these three sources lie either on or 0.5–1.0 dex above the star-forming main sequence at z = 4–6 and have undergone a recent burst of star formation. The sources have extended rest-UV/optical morphologies with no evidence for a dominant point source component, indicating that an AGN is unlikely to dominate their rest-UV and optical emission. Two of the sources have complex, multi-component rest-frame UV/optical morphologies, suggesting that their starbursts may be triggered by merging activity. These HzRSs open up a new window towards probing radio emission powered by star formation alone at z > 4.5, representing a remarkable opportunity to begin tracing star formation, independent of dust, in the early Universe.