  Triple heavy vector boson production, $p p \to VVV$ $(V = W, Z)$, has
recently been observed for the first time. We propose that precision
measurements of this process provide an excellent probe of the first generation
light quark Yukawa couplings. Modified quark interactions with the off-shell
Higgs in this process lead to a rapid growth of the partonic cross sections
with energy, which manifests in an enhanced $p_T$ distribution of the final
state leptons and quarks. We quantify this effect and estimate the present and
future 2$\sigma$ sensitivity to the up, down, and strange Yukawas. In
particular, we find that HL-LHC can reach $\mathcal{O}(400)$ sensitivity to the
down Yukawa relative to the Standard Model value, improving the current
sensitivity in this process by a factor of $10$, and which can be further
improved to $\mathcal{O}(30)$ at FCC-hh. This is competitive with and
complementary to constraints from global fits and other on-shell probes of the
first generation Yukawas. The triboson sensitivity at HL-LHC corresponds to
probing dimension-6 SMEFT operators suppressed by an $\mathcal{O}(1)$ TeV
scale, similarly to other LHC Higgs probes.
