Young Japanese women are flocking to pools on summer evenings — but not so much to swim as to shine on social media.

Women in their teens and 20s are putting on their bathing suits and heading to "night pools" at upscale hotels and other tourist facilities in major cities, where they spend time taking selfies with friends on inflatable tubes and sipping cocktails at poolside.

The night pool at Hotel New Otani in Tokyo opened for business on July 21. A DJ cranks out music in the background as partygoers revel among illuminated palm trees creating a tropical atmosphere. At ¥8,000, admission is not cheap.