  We study the giant gravitons in the $AdS_4$ bagpipe geometries involving
end-of-the-world (ETW) brane constructed by a single $5$-brane and either two
stacks or one stack of D3-branes in Type IIB string theory. From the exact
formulae and giant graviton expansions of the half-indices for the half-BPS
boundary conditions and interfaces in $\mathcal{N}=4$ super Yang-Mills theory,
we obtain the BPS spectra of the fluctuation modes of the $AdS_4$ bagpipe
geometries including the ETW brane region.
