In this study, we aim to introduce the concept of classical 1-absorbing prime submodules of a nonzero unital module \(M\ \) over a commutative ring \(A\ \) with unity. A proper submodule P of M is said to be a classical 1-absorbing prime submodule, if for each \(m\in M\) and nonunits \(a,b,c\in A,\) \(abcm\in P\) implies that \(abm\in P\) or \(cm\in P\) . We give many examples and properties of classical 1-absorbing prime submodules. Also, we investiage the classical 1-absorbing prime submodules of tensor product \(\ F\otimes M\) of a (faithfully) flat A-module F and any A-module \(M.\ \) Furthermore, we determine classical prime, classical 1-absorbing prime and classical 2-absorbing submodules of amalgamated duplication \(M\bowtie I\) of an A-module \(M\ \) along an ideal I. Also, we characterize local rings \((A,\mathfrak {m})\) with \(\mathfrak {m}^{2}=0\) in terms of classical 1-absorbing prime submodules.
