When dusk falls, young women in Japan are changing into their bikinis and hitting the pools.
If you thought these ladies are taking a night-time dip to cool down during hot summer nights, you're wrong.
They are swapping dance floors for hotel swimming pools as 'night pools' have become as the trendiest nightspots in Tokyo and beyond.
The #nightpool trend has women all made up and dressed in cute swimsuits for pool parties, Kyodo News reported.
In pools illuminated by pretty neon lights, they can be seen lounging on swan floats, sipping their cocktails from the poolside, or dancing to booming tunes from the DJ booth.
Although night time pool parties are not something new, they have seen a resurgence in popularity over the past few years thanks to the proliferation of social media.
And it is easy to see why 'night pool' is a hit with the millennials - they don't have to worry about getting tanned or sharing the pool with boisterous children.
'Night pool' the new nightspot for Japanese millennials
But what's most important to these young women at night time pool parties? Selfies.
"I won't swim because my makeup and hair would get messed up," a university student told Kyodo News.
The pools are designed to be Instagram worthy, and many youngsters have come up with the most creative ways to pose for photos to be shared on social media.
Hotels and theme parks are benefiting from this new trend too, with numerous hotels such as Prince Hotel Tokyo, New Otani Hotel, Sheraton, and theme parks like Laguna Ten Bosch holding 'night pool' parties.
Partying at these locations does not come cheap though. Admission fees can range from 1,950yen (S$24) at Laguna Ten Bosch to 8,000 yen (S$98) at rooftop hotel pools.
While these pool parties look really fun, let's hope that no one relieves themselves in the water.