It shouldn't count steps. That would be silly. It should count swim strokes. According to the specs Garmin Venu counts swim strokes: https://buy.garmin.com/en-US/US/p/643260/pn/010-02173-11#specs
Are…
This has been discussed in a number of forums. It may not be able to distinguish the accelerometer reading differences as both walking and swimming (crawl) have somewhat similar profiles. But it conceivably could be disabled in future releases during swimming as HR is.
It shouldn't count steps. That would be silly. It should count swim strokes. According to the specs Garmin Venu counts swim strokes: https://buy.garmin.com/en-US/US/p/643260/pn/010-02173-11#specs
Are you measuring your activities in how many steps you take? Do you have to report the number of steps you take per day to someone or why is it interesting? It is better to report the type of activity, time and distance. If you really want to have steps counted during your swim then select another activity type that counts steps and then change to swimming afterwards.
Forerunner 945 got Swimming dynamics and counts my strokes.