Measurements of the magnetic penetration depth λ in the Fe-based superconductor Ba1−xRbxFe2As2 (x=0.3, 0.35, 0.4) were carried out using the muon-spin rotation (μSR) technique. The temperature dependence of λ is well described by a two-gap s + s-wave scenario with a small gap Δ1 ≈ 1–3 meV and a large gap Δ2≈7–9 meV. By combining the present data with those previously obtained for RbFe2As2 a decrease of the BCS ratio 2Δ2/kBTc with increasing Rb content x is observed. On the other hand, the BCS ratio 2Δ1/kBTc is almost independent of x. In addition, the contribution of Δ1 to the superfluid density is found to increase with x. These results are discussed in light of the suppression of interband processes upon hole doping.