Although I have seen a Willet in flight it is more common to see them walking the shore, poking the surf and sand for food.
I didn’t see where he captured this fish but he took it to a wide open expanse of beach to consume it, alone. It’s size slowed him down. Just swallowing it wasn’t an option.
The pools left by the falling tide attract the Willets. Calmer than the ocean surf they often are a concentrated food source as the water drains away.
They will completely immerse their heads looking for food, tipping like a bobbing garden ornament.