A Queens couple says their relaxing vacation turned into a nightmare after they discovered a complete stranger casually hanging out inside their luxury apartment — and allegedly using keys to get back in.

Bill and Yelim Kim were thousands of miles away from their Long Island City home on July 24, enjoying the final night of a trip to Yellowstone National Park, when their home-security system suddenly sent them an alert.

Someone was inside their apartment.

When the couple checked the live camera feed, they were stunned.

A woman they did not know was reportedly walking around their apartment, helping herself to a drink and lounging on their couch as if she lived there.

“It was panic, panic, panic,” Yelim told The Post.

Bill said he initially struggled to believe what he was seeing.

“I was in disbelief. I just could not believe what I was seeing,” he told FOX 5.

But the situation became even more frightening when the woman apparently noticed the security camera.

Surveillance footage showed her walking over to the device and ripping it from the bookshelf.

The couple immediately began recording the footage while scrambling to figure out what to do from hundreds of miles away.

“If we didn’t have a security camera set up, would she have just stayed?” Bill said.

“This was almost 11 p.m. at night. Would she have slept in our bed?”

Instead of spending their final evening relaxing after a long day, the couple found themselves calling police and friends from their yurt in the national park.

Yelim said she had to convince police that the situation was real and not some kind of prank.

Two of the couple’s friends eventually rushed to their Long Island City building while police were on their way.

One of the friends even knocked on the apartment door and confronted the woman.

Yelim admitted that her friend’s decision was both courageous and risky.

“It was incredibly stupid and brave for him to do that,” she said.

The woman initially left the apartment after being told to go.

But the nightmare was far from over.

According to Yelim, the woman returned just minutes later and used keys to let herself back inside.

“My friend sees her fumbling through keys in her hand. So there was more than one [set of keys], and she uses one of them to open the door and come in,” Yelim said.

Police soon arrived, and the woman was taken away in an ambulance.

The couple later learned that building management believed the woman had posed as a dog walker and was allowed upstairs by a doorman, according to emails sent to residents.

The doorman was subsequently removed from the property, while management said additional security measures would be implemented.

But the Kims say the frightening saga did not end there.

Two days after the original incident, the woman reportedly showed up at the building again.

She allegedly claimed she was there to meet someone and attempted to gain entry.

This time, she was turned away.

For Yelim, seeing the woman again was terrifying.

“We were scared. I had like a full stomach ache when I saw her,” she said.

“I just, I could not believe that she was back here.”

The woman was reportedly wearing the same dress and heels she had worn during the original incident and appeared visibly distressed.

Bill also noticed that she was wearing a hospital bracelet.

“It seemed like she got discharged from the hospital and just came straight [back],” he said.

The woman has not been publicly identified and has not been charged with a crime.

The NYPD is investigating the incident as a burglary.

The Kims said nothing appeared to have been stolen from their apartment.

Still, the couple say the experience has left them deeply shaken.

Their apartment, once considered their safe place, no longer feels that way.

Bill said they feel “terrible” being back inside.

“It doesn’t feel like a safe space for us anymore,” he said.

Yelim said she feels violated by what happened.

“I’m freaking traumatized. I don’t know how else to, you know, describe it,” she said.

The couple had been planning to renew their lease in September.

Now, they say they are urgently searching for another place to live.

“We can’t be here anymore,” Bill said.

The couple’s claims about how the woman gained access and the building’s security procedures remain under investigation.