  We study classical closed bosonic strings probing the near-horizon region of
a non-extremal black hole and show that this corresponds to understanding
string theory in the Carroll regime. This is done by first performing a Carroll
expansion and then a near-horizon expansion of a closed relativistic string,
subsequently showing that they agree. Concretely, we expand the phase space
action in powers of $c^2$, where $c$ is the speed of light, assuming that the
target space admits a string Carroll expansion (where two directions are
singled out) and show that there exist two different Carroll strings: a
magnetic and an electric string. The magnetic string has a Lorentzian
worldsheet, whereas the worldsheet of the electric string is Carrollian. The
geometry near the horizon of a four-dimensional (4D) Schwarzschild black hole
takes the form of a string Carroll expansion (a 2D Rindler space fibred over a
2-sphere). We show that the solution space of relativistic strings near the
horizon bifurcates and the two sectors precisely match with the
magnetic/electric Carroll strings with an appropriate target space. Magnetic
Carroll strings near a black hole shrink to a point on the two-sphere and
either follow null geodesics or turn into folded strings on the 2D Rindler
spacetime. Electric Carroll strings wrap the two-sphere and follow a massive
geodesic in the Rindler space. Finally, we show that 4D non-extremal Kerr and
Reissner-Nordstr\"om black holes also admit string Carroll expansions near
their outer horizons, indicating that our formulation extends to generic
non-extremal black holes.
