Embodiments provide a coupling system (3) for an ostomy appliance (1) comprising a sealing wafer (5) and a collecting bag (7). The coupling system comprises a first coupling part (9) and a second coupling part (11). The first and second coupling parts each encircle a stoma-receiving opening (17). The first and second coupling parts are configured to connect the sealing wafer to the collecting bag. The first coupling part comprises a first base portion (33), a second base portion (35) and a connecting portion (37) extending between the first and second base portions. The first base portion is arranged radially closer to the stoma-receiving opening than the second base portion. The first coupling part comprises an enclosed volume of air (10). The enclosed volume of air is enclosed at least in part by the first base portion, the second base portion and the connecting portion.
