This should not be a problem, as it is basically waterproof and designed for swimming (not for diving). However, salt water attacks the silicone seals over time and makes them brittle (the same applies to chlorinated water in indoor swimming pools). Therefore: always rinse under clear water after the water bath (which is the case when showering anyway).

Above all, you must be careful not to press the button in or under water, as this can cause water to penetrate the watch. At least my Fenix 3 was waterproof up to 10 ATM after 3 years. Garmin briefly mentions under care instructions that no buttons should be pressed under water if possible. For me, this is more of a joke, as it does not make the watch waterproof. Waterproof for my definition also means full functionality.