This is whaley cool.

Two big and beautiful whale sharks were spotted gliding off the shores of New York City Monday in a “rare” sighting.

The endangered species, the largest known fish in existence, swam right up to the American Princess twice during their expedition 100 miles into the Atlantic — just one day after International Whale Shark Day.

Two whale sharks investigated the boat 100 miles south of the Big Apple. Chris St Lawrence

Incredible video shows one of the endangered creatures showing off its bespeckled back to dozens of elated gawkers before plunging back into the depths of the ocean.

“It was nuts! There were a lot of birds feeding and then next thing you know this massive whale shark comes right up next to us in that crystal clear blue water,” said Chris St. Lawrence, a naturalist with American Princess Cruises who filmed the breathtaking footage.

The jaw-dropping encounters unfolded near the Hudson Canyon, a 2.5-mile-deep and 250-mile-long cavern connected to the Hudson River and home to a rich and diverse ecosystem of wildlife.

While whale sharks are known to frequent the area, it’s pretty rare to catch a glimpse of one of the gentle giants swimming in the open water.

The Brooklyn-based American Princess was on the tail end of a 24-hour pelagic trip to the canyon when the first 20-ton beast curiously investigated the vessel’s port side.

“It’s pretty rare to see from a boat because they live their whole lives underneath the surface, so they can be hard to see and it’s so difficult to get out there,” said St. Lawrence, who also works for whale research group Gotham Whale. “But the whole night out there, I was telling everybody that that was the thing I wanted to see the most on that trip.”

The trip was especially fruitful — the group also spotted whitetail tropic birds and a juvenile Sabine’s Gull, both species that are rarely seen in New York, as well as a leatherback sea turtle, a humpback whale mother and her calf, yellowfin tuna and more.

St. Lawrence theorized that the warmer weather from the Gulf Stream may have brought the whale shark and other tropical birds into the area, but warned that there is not enough known about whale sharks to know for certain why they may be playing in metro waters.

The harmless sharks were placed on the endangered species list in 2016 and continue to face population struggles from vessel strikes, bycatch, fishers, finning and climate change, according to the International Union for Conservation of Nature.

Researchers estimate there are only about 200,000 whale sharks left in the world and are only a third of the way towards a full recovery.

The National Oceanic and Atmospheric Administration is in the early stages of designating the Hudson Canyon as a National Marine Sanctuary to better protect it as a home for whale sharks and other vital marine life.