  We treat prospects for multimessenger astronomy with giant flares (GFs), a
rare transient event featured by magnetars that can be as luminous as a hundred
of the brightest supernovae ever observed. The beamed photons could correlate
with an axion counterpart via resonant conversion in the magnetosphere. In a
realistic parameter space, we find that the sensitivity limit to galactic GFs
for currently viable experiments is $\mathrm{g}_{\phi
\gamma}\!\gtrsim\!\mathrm{several}\!\times\!10^{-13}$ GeV$^{-1}$ \&
$\mathrm{g}_{\phi e}\!\gtrsim\!\mathrm{few}\!\times\!10^{-12}$. We rule out the
compatibility of axion flares with the recent XENON1T excess only due to the
time persistence of the signal.
