We pursue the intriguing possibility that larger-size instantons build up diffractive scattering, with the marked instanton-size scale \langle \rho \rangle \approx 0.5 fm being reflected in the conspicuous ``geometrization'' of soft QCD. As an explicit illustration, the known instanton contribution to DIS is transformed into the intuitive colour dipole picture. With the help of lattice results, the q\bar q-dipole size r is carefully increased towards hadronic dimensions. Unlike pQCD, one now observes a competition between two crucial length scales: the dipole size r and the size \rho of the background instanton that is sharply localized around \angle \rho \rangle \approx 0.5 fm. For r \gtrsim \langle \rho \rangle, the dipole cross section indeed saturates towards a geometrical limit, proportional to the area \pi \langle \rho \rangle ², subtended by the instanton.

PACS numbers: 12.38.Aw, 13.60.Hb