Florian Wellbrock of Germany and Arianna Bridi of Italy were the winners of the eighth and final leg of the International Swimming Federation (FINA) Marathon Swim World Series in Abu Dhabi.
The overall men's and women's titles went to Rio 2016 champion Ferry Weertman of The Netherlands, who finished seventh on the day, and Brazil's Ana Marcela Cunha, who confirmed her fourth overall victory since 2010 by finishing third behind Bridi and her Italian compatriot Rachele Bruni.
A total of 74 men and 46 women completed the 10 kilometre race in the United Arab Emirates city.
Elsewhere in the country's capital, the preliminary competition took place for tomorrow's final two rounds of the 2018 FINA High Diving World Cup.
Wellbrock touched in 1 hour 53min 00.9sec in a close finish that saw Italy's Gregorio Paltrinieri take silver in 1:53.01.4 and Kristof Rasovszky of Hungary bronze in 1:53.01.7.
Bridi won by a clearer margin in 2:00.21.8, in front of Bruni, who clocked 2:00.25.7, and Cunha, who was timed at 2:00.26.2.
It was the second win of the year for both victors on the day, with Wellbrock having previously won in Lake Balaton and Bridi having been first in the Seychelles.
Wellbrock, who is also a pool swimmer, is now seeking to compete in the 1,500 metres freestyle and 10km marathon swimming race at the 2020 Olympics in Tokyo.
"I'll try to qualify for both," he said.
"Here, it was an easy race - the water was quite flat, so I could imagine swimming in a pool."
Bridi, winner of the Series in 2017, said: "My tactics was to stay as much as possible in the pack, and then push faster in the last kilometre.
"It worked quite well and I even managed to arrive comfortable to the finish."
Cunha, meanwhile, was celebrating a latest overall triumph following her efforts of 2010, 2012 and 2014.
Silver was enough to give Bruni overall second place in front of the Rio 2016 champion Sharon van Rouwendaal of The Netherlands.
"This is a year without World Championships, so this is the main competition for us," said Cunha.
"Now, it's time to take a short break and to prepare for 2019, where we will have the FINA World Championships in Korea.
"We will be in all individual events, plus the team, so we hope we can do well, and, who knows, get a fourth title in the 25km."
The Brazilian has accumulated nine medals at FINA World Championships, including three victories over 25km in 2011, 2015 and 2017.
Weertman had enough points to maintain his advantage, as his main challenger, Jack Burnell of Britain, could only manage 12th place in the UAE.
"It's the first time for me that I managed to compete in the Series and win," said Weertman.
"I had Olympic, world, and European titles - only the World Series was missing.
"Now, it's done.
"And now, it's train, train and train to make the cut for the Olympics in 2020."
Jonathan Paredes of Mexico is the provisional leader in the FINA High Diving World Cup after the initial two dives, displaying an excellent technique and performing very clean entries into the water.
He totalled 204.40 points, scoring a perfect 10 on his second attempt.
His main challengers are Gary Hunt of Britain, seeking a third consecutive World Cup title and currently second with 192.15, and 2017 world champion Steve LoBue of the United States, third on 191.00.
Romania's Constantin Popovici, a former pool diver who is making his debut in the high diving world, stands fourth on 187.05.
Among the women, with 12 entries, the fight for the gold looks like being between Rhiannan Iffland of Australia, the 2017 world champion and silver medallist of the previous World Cup, and Lysanne Richard of Canada, the winner of the 2016 World Cup.
Ahead of the final day the Australian is leading with 150.15, but the Canadian is not far off with 146.00.