In my experience, since the 'Tides' function is an activity and not a widget (something I don't understand in itself and complained about earlier), it is impossible to view tide data during an actual sports-activity (like surfing, hiking etc.). Even if I pause my current activity and try to get to the list of activities by pressing the top-right GPS button from the main watch-face the only option I have is to resume paused activity...
I totally get why two activities at the same time can not be allowed, but that just serves to show why Tides should not be an activity but a full-fledged widget in the first place...
Anybody figured out a workaround?