Not a Ricoh specific one exists that i know of, but there is these ones which you attach on it by the filterthreads, like Thinktank etc brands, there are more heavyduty ones and those that is more like a plastic bag only, you need a filteradapter on the camera, either original or 3rd party like Nisi.
If there comes a few drops and you wipe it of immediatly and protect the camera otherwise, then there should be no worries, but these aint actioncameras.
I've had a ziplock bag with me on travels for these, it has done the job well.
The original GR i didnt bother to protect, but noticed that when after 9.5 years of use i opened it to clean it inside, that it was much tighter assembled and thus better protected than the III & IIIx (own and have owned).