Three hours before their team’s opening World Cup match on 14 June, about 4,000 football fans are expected to pack into a giant former concrete grain store in Rotterdam that is one of the Dutch city’s best-known nightclub venues.

However, the flags will be blue, not orange, and the aroma of arros moro will fill the air as the room pulsates to the beat of conga drums and ritmo kombina. The Maassilo has been booked to host the watch party for Curaçao, the least populous country to qualify for the World Cup and a constituent nation of the Kingdom of the Netherlands.

Many Dutch supporters will be cheering along with them. All but two of Curaçao’s squad were born in the Netherlands; 12 of them play for clubs in the Eredivisie or the second-tier Keuken Kampioen Divisie.

The team are managed by the longtime Dutch coach Dick Advocaat. The Dutch king and queen are planning to attend at least one of the Blue Wave’s group matches.

“It’s not just historic for Curaçao: it’s historic for the Netherlands,” said Sontje Davelaar, 41, a DJ for the community radio station Fortius, which is organising the watch party. “Curaçao is a son of the Netherlands. For the first time we’re going to the World Cup together as a family.”

Dutch football fans are renowned for turning stadiums and host cities into a sea of orange wherever they go. But in Rotterdam, a city where one in three residents were born abroad and 60% have a non-Dutch background, the picture is more varied.

Cape Verde, an archipelago off the north-west coast of Africa, is another nation making its World Cup debut. Six of its squad were born in Rotterdam, a city nicknamed “the 11th island” by Cape Verdeans because of its 20,000-strong emigrant population.

“This place will be packed,” says Alexander Soares Silva, an administrator at FC Maense, a community football club founded by Cape Verdeans 48 years ago. Sitting in the basement of the São Nicolau cultural centre, he describes how he had to watch Cape Verde’s historic final qualifying match on his phone outside the door because there was no room inside.

Cape Verdeans started arriving in Rotterdam in the 1950s, during the struggle for independence from Portugal, to work on Dutch ships. “We’re known as the silent migrants,” Soares Silva, 43, says. “We’ve been here three generations but the rest of Rotterdam doesn’t know us. Now people see us on ESPN, they know who we are and we can be proud of our roots.”

The mayor of Rotterdam, Carola Schouten, hopes the tournament will bring the city’s communities together. The council has relaxed its licensing hours during the World Cup so that as many games as possible can be shown on outdoor screens, including Curaçao and Cape Verde’s matches against Germany and Spain respectively.

“We are cheering on five teams during this World Cup,” she said. “I think it’s great that there are so many places where people can watch together and support each other’s teams.”

Morocco and Turkey have qualified and will each be cheered on by 50,000 Rotterdammers. When Morocco beat Portugal to reach the semi-finals in Qatar four years ago with a team featuring several players born and raised in the Netherlands such as the then Chelsea player Hakim Ziyech, hundreds of fans converged in the city centre, flying red and green flags and setting off fireworks.

There are three Dutch-born players in the Morocco squad this time, including the Manchester United defender Noussair Mazraoui. Dutch Moroccans do not tend to opt for the country of their birth: the last to wear the famous orange jersey was Ibrahim Afellay a decade ago.

“It’s become a loyalty issue,” said Lotfi El Hamidi, a Rotterdam-born journalist who wrote a book, Generation 9/11, about the experience of Muslims growing up in Europe in the 21st century.

It reflects a wider sense among Dutch Moroccans they are only ever “provisional” members of society, a feeling that has sharpened with the rise of far-right parties such as Geert Wilders’ Party for Freedom (PVV) in the last 30 years, he added.

“They’re expected to choose the Netherlands because they have Dutch passports,” El Hamidi says. “But when they do, they notice they’re under a magnifying glass. If things go badly, they’re the ones who get singled out for criticism. Whereas if they play for their parents’ country, they get the red carpet treatment.”

The debate is likely to intensify if Morocco meet the Netherlands on the pitch, which could happen as early as the second round. “Some Moroccans won’t care either way, but there is a section who will be hoping Morocco wins, so they can say: we’re not inferior to you,” El Hamidi says.

Yet for many fans in Rotterdam, loyalties are shared, not divided. “We start out supporting different teams, but as the other countries drop out we all follow Oranje [the Dutch national team],” El Hamidi says. “It’s just that not everybody does it with the same intensity.”

“Rotterdam is a very multicultural city,” adds Soares Silva. “I have Turkish neighbours and Antillean friends. I was so proud when Morocco became the first African nation to get to the semi-finals. When Curaçao qualified I actually set my alarm for their final game. I was so happy when they made it.”