Lost iphone in beach

So we were just standing on the shore of Varkala beach and suddenly a wave came which just pushed us down and the iphone fell out of my pocket and immediately it was gone. What should I do? Any chance I can get back the dead phone even? It happened around 4:30 to 5pm. What next steps should I take? Tried calling phone but out of network(obviously!), can't see any location on iCloud> find my device.

It's really distressing and spoiled my trip. Please share your opinions, suggestions and comments.