I own multiple G-Shock watches, and this is by far the most disappointing.
The tide function is completely inaccurate. Even after setting my correct location through the Casio Watches app, the displayed tide data is nowhere near actual conditions. That makes the feature effectively useless.
The only reason I bought this watch was for the tide function, as I already own the Casio GBD200, which does everything else just as well. Unfortunately, this model fails at the one job it’s supposed to do.
If you’re buying this watch for tide information, don’t, unless you’ve confirmed it works properly in your area.