We have measured the penetration depth of overdoped Y 0.9 Ca 0.1 Ba 2 Cu 3 O 7− δ (Ca-YBCO) thin films using two different methods. The change of the penetration depth as a function of temperature has been measured using the parallel-plate resonator (PPR), while its absolute value was obtained from a quasi-optical transmission measurement. Both sets of measurements are compatible with an order parameter of the form Δ d x 2− y 2+ iδ d xy, with Δ= 14.5±1.5 meV and δ= 1.8 meV, indicating a finite gap at low temperature. Below 15 K, the drop of the scattering rate of uncondensed carriers becomes steeper in contrast to a flattening observed for optimally doped YBCO films. This decrease supports our results on the penetration depth temperature dependence. The findings are in agreement with tunneling measurements on similar Ca-YBCO thin films.