Eleven storeys above the crowds, cars and commuter trains in Tokyo’s Shibuya fashion district, 15 men and women are in the midst of an intense post-work scrimmage. They’re playing futsal, a five-a-side version of football, under floodlights on the rooftop of a department store; their vertiginous choice of venue doesn’t seem to be diminishing their enthusiasm for the game.

By day they are merely colleagues at Tokyu Corporation, a railway and resort operator and property developer. But here at the Adidas Futsal Park the rigid office hierarchy and division rivalries melt away; they dash, dribble, shoot and score on the artificial turf for two hours until 22.00. While the pace is fast there’s also a rapid-fire back-and-forth of jokes and laughter. Just beyond the net that surrounds the field to keep balls from going over the edge, a giant monitor on the side of a building plays a continuous loop of TV commercials for cosmetics.

Until Tokyu opened the field in 2001, nobody in Japan had ever thought to put a football pitch on top of a tall downtown building. And why not? There’s almost never a time now when the field isn’t in use.

“Our office is down the street so we can say bye to our colleagues and be here ready to play five minutes later,” says Satoshi Segawa, who organises the gathering at least once a month. He’s carrying on a tradition at Tokyu that goes back more than two decades. “We have footballers of all levels. It’s informal and a good way to get to know colleagues.” Afterwards they grab a drink before catching their trains home.

The end of the workday marks the start of a citywide migration to playing fields, practice ranges and running tracks. But with strict rules on activities in Tokyo’s public parks and fierce competition to book time on a field or court, the best workout spots are often in the most unlikely places. Rooftops, for instance: baseball batting cages, driving ranges for golfers, skateboarding parks, basketball courts and archery ranges. “It’s normal in Tokyo to make use of the limited space there is,” says Takao Nishikata.

Normal for Nishikata, who has spent the past two decades teaching tennis at the rooftop Takadanobaba Citizen Plaza Tennis School, on the city’s west side. The school offers once-a-week lessons and most evenings the four well-lit courts are packed. Lessons aren’t one on one; 13 people share a court, taking turns smacking balls diagonally from all four corners and practising serves and volleys. It’s a smart formula for a tennis school and everyone is breathing hard and sweating by the end. “I’m hooked,” says Yuki Muraoka, who works at Sony and took up tennis five years ago for exercise. “This is close to where I live and I can come on any weekday once a week.”

Even in the city’s dense centre, there’s room to exercise at street level if you know where to look. In the Higashi-Ginza district, 20 runners limber up in front of fashion retailer United Arrows’ sportswear outlet En Route. They’re here for the shop’s weekly 19.30 run, a 5km to 10km trot that’s open to anyone who wants to join. Most participants find out about it from the staff while shopping or from En Route’s Instagram feed.

“I get so motivated running with this group,” says Kazue Wada, a 35-year-old hair stylist who is a regular. “It’s a casual, slow run with fun people.” As the runners thread their way past closet-sized bars along a raised section of railway track, a group of onlookers cheers. “That’s one of the nice things about running with a group right through the centre of town,” says Wada.

From May to October, days in Beirut become long, torturous and sweaty. Only once the working day ends and the evening begins can its residents escape the stifling heat of the car-clogged streets and head to the city’s cooling stretches of Mediterranean coastline.

For most this means the Corniche, where the endless tower blocks and snarling traffic give way to a seaside esplanade: uninterrupted, several kilometres long and wide enough to accommodate a cycle lane, benches, palm trees and gaggles of pedestrians (a real rarity in Beirut).

“There’s no space like this in Dahiyeh. The kids can really play here,” says Maya Shemali, a 30-year-old saleswoman from Beirut’s southern suburbs, colloquially known as Dahiyeh among locals. “And I love looking at the sea.”

“Beirut is all about buildings,” says Nadine Ahmar, a 22-year-old tax consultant strolling with her younger sister and dog at sunset. “Here there is space and we can breathe.”

In a city with few large public spaces, children and dogs are not the only ones who flock to the Corniche in the evenings to let loose. Abed Ghazail, a personal trainer, comes to the area every day just before dusk to run, swim and cycle. “This is a place of fitness for me,” he says. “I couldn’t live without it.”

As night falls and the yellow glow of streetlights replaces the sun, the well-dressed joggers, dripping cyclists and gangs of showy male divers are joined by musicians, lovers walking hand in hand and revellers. Arabic music is blasted from parked cars as shisha pipes are set up and people share bench picnics of yellow lupin beans, freshly roasted corn on the cob and trays of lemon-soaked carrot slices bought from nearby food carts. Mohammad al-Njemet, a 20-year-old student, comes to the Corniche to play his distinctive style of Arabic-infused flamenco music on his guitar. “I like to watch the sea while I play,” he says. “It inspires me.”

Just down the road in the abandoned shell of the fabled St Georges Hotel – a hub for Beirut nightlife until the civil war and now a subject of much controversy – the young and beautiful begin to gather for a weeknight party that will continue into the early hours. Dancing on the hotel’s large terrace with its sweeping views of Zaitunay Bay, Jennifer Moubarak, 23, says it is the perfect summer haunt. “I love being able to see the sea as I dance. The other clubs feel like a cage in comparison.”