King Willem-Alexander and Queen Máxima of the Netherlands
As honorary member of the IOC, King Willem-Alexander will fulfil his duties and support the Dutch team, alongside the country's Prime Minister Mark Rutte and Minister of Health, Welfare and Sport, Edith Schippers.
The king will be in Brazil from 4 to 6 August and will attend the opening ceremony, most likely with his Argentinean wife Queen Máxima.
At the family's summer photocall, the king did not rule out taking his three daughters to the Games for the experience.
Queen Silvia and King Carl XVI Gustaf of Sweden
The king and queen of Sweden are due to attend the Games from August 16 to 21. While they will miss the opening ceremony, Silvia and Carl Gustaf will be guests of honour at the closing ceremony alongside other European royals.
Silvia, who is half Brazilian, and Carl Gustaf are another royal couple who have the Olympics to thank for their love story.
boarAt a party during the 1972 Munich Olympics, Carl Gustaf, the heir to one of Europe's most ancient thrones, spotted official hostess Silvia, who as a trained interpreter fluent in five languages, was there to take care of guests.
The chance meeting led to a lasting love match, of which Carl Gustaf would tell reporters: "When I first saw her it said 'click' and it has kept clicking ever since."
King Felipe and Queen Letizia of Spain
One week before the opening ceremony, Felipe and Letizia waved off the Spanish team at a Madrid airport. The king delivered a speech, wishing all 305 sportsmen and women the best of luck and calling them "Spain's great team".
Among those representing the country is tennis star Rafael Nadal, who will act as the nation's official flagbearer at the Games.
Felipe and Letizia, who aptly wore a red T-shirt, took selfies with the athletes before the competitors boarded their flight.
It is not yet known whether the king and queen will attend this year's Games, although the couple were regular fixtures at the London 2012 Games and the Beijing 2008 Games.
Queen Mathilde and King Philippe of Belgium
Belgium's king and queen are set to attend the opening ceremony of Rio 2016, and will also stay on for other sporting events to support the Belgian team.
During their trip to Brazil, Philippe and Mathilde will meet athletes at the Olympic Village as well as Thomas Bach, former Olympic fencer and president of the International Olympic Committee.
The royals will also visit social project Kiyo/Amar, which helps street children living in the suburbs of Rio.
Prince William, Kate and Prince Harry
The Duke and Duchess of Cambridge and Prince Harry have opted out of the Games this year. A royal source told HELLO!: "It was under consideration at some point that some or one of them might go, but for a whole range of reasons they are not going."
William, Kate and Harry have other overseas trips lined up in the coming weeks, including the Duke and Duchess' royal tour of Canada in the autumn, and HELLO! understands that this was a factor in the decision.
Prince Harry visited Brazil in 2012 and again in 2014, even venturing into the notorious Cracolandia district of Sao Paulo – Brazil's crack cocaine capital – so security is unlikely to have been a major concern this time around.
Princess Anne
Instead, the British royal family will be represented by the Queen's daughter Princess Anne, who is a member of the IOC.
The Princess Royal will cheer on Team GB's athletes at the opening ceremony and other fixtures until she departs on 12 August.
Her equestrian daughter Zara Tindall, who won a silver medal at the London 2012 Olympics, was not selected for this year's eventing team.
Prince Albert and Princess Charlene of Monaco
Despite being a former Olympic swimmer, Princess Charlene of Monaco is also unlikely to make the trip to Brazil this year.
Her husband Prince Albert revealed that his wife has decided to stay at home due to concerns over the Zika virus, coupled with her desire to be with the couple's children, one-year old twins Prince Jacques and Princess Gabriella, who she believes are too young to make the trip to Brazil.
"First, she has decided not to go because she couldn't stand to be away from the babies for two weeks and they're really not old enough to support the trip," Prince Albert told People.
"She has important health concerns. She doesn't like what she's been reading and hearing about the Zika virus and some other health issues."
The royal couple's relationship with the Olympics run deep, given that both are former Olympians and made their first public appearance together at the 2006 games in Turin.
As an active IOC board member, Albert will fulfil his duties in Rio, although he has revealed that he has shortened his visit to ten days.
Princess Marie and Prince Joachim of Denmark
Frederik's younger brother Prince Joachim will also attend the Games with his French wife Princess Marie.
The couple will be present from 29 July to 8 August and attend the opening ceremony with Prince Frederik and Princess Mary.
Marie and Joachim will support the Danish athletes at various sporting events, and on 4 August they will be guests of honour at a concert by Danmarks Radio's Danish National Girls' Choir.
The couple are in the country with their children, earlier this week they posted a family picture from the world-famous Iguazu Falls while travelling en route to the Rio Olympics.
Crown Princess Mary of Denmark and Crown Prince Frederik
The future king and queen of Denmark are already in Rio de Janeiro. The couple flew to Brazil on 31 July and while Mary will stay for the first week of the Games, Frederik will see the sporting event to the end, as member of the International Olympic Committee.
They have a number of engagements scheduled, including the opening ceremony on Friday 5 August, as well as the opening of the Danish Pavilion three days prior.
A highlight for royal watchers will be Mary and Frederik's attendance at a special gala dinner on the training ship Danmark on 3 August, where the couple will don their finest gladrags.
The royals will also sit down for a special IOC President's dinner on 4 August.
The Olympics hold a special place in the couple's heart. Back in 2000 at the Sydney Games, Mary and Frederik met in a crowded Sydney pub, the Slip Inn. Three years after that chance meeting the couple became engaged and they are now happily married with four children.