Argentina’s Victoria Travascio and Maria Branz occupy first place in the 49erFX after the opening day of action at the Sailing World Cup Final on Santander Bay.
The top five teams are split by only three points with Travascio and Branz on four in front of Great Britain's Kate Macgregor and Sophie Ainsworth following the first three races.
Brazil's Martine Grael and Kahena Kunze sit level on six points with Singapore’s Kimberly Lim and Cecilia Low, while France’s Lili Sebesi and Albane Dubois are fifth with seven.
"It was a pretty good first race," Low said.
"We were easing into it."
Lim added: "We got a good understanding of the race area from our first race and that helped with the rest of the day."
In the 49er, Poland’s Lukasz Przybytek and Pawel Kolodzinski are tied for the lead on five points with Britain’s James Peters and Fynn Sterritt.
Three races were held with wins going the way of the Polish pair, Britain’s Jack Hawkins and Chris Thomas and Argentinean brothers Yago and Klaus Lange.
Switzerland’s Mateo Sanz Lanz is the frontrunner in the men’s RS:X after finishing second in the opening race, first in the second and ninth, which he discards, in the third.
He holds a two-point advantage over nearest challenger Shahar Zubari of Israel.
France’s Thomas Goyard is a further one point back on six.
In the women's RS:X, Brazil's Patricia Freitas is first overall followed by Israel's Katy Spychakov and China's Yunxiu Lu.
Home favourites Fernando Echavarri and Tara Pacheco got better as the day progressed in the Nacra 17.
A third, followed by a second and then a first puts them in control at the early stages of the event.
British pairings John Gimson and Anna Burnet and Tom Phipps and Nicola Boniface trail the Spaniards by one point.
World Cup winner Nicolas Parlier of France was the form rider in the formula kite with five race wins out of six in the yellow fleet handing him the overall lead.
Britain’s Guy Bridge won three races in the blue fleet and is second overall.
Defending World Cup Final champion Oliver Bridge of Britain is down in sixth place.
In the 470 class, Japan's Ryo Imamura and Jumpei Hokazono controlled the men's division and registered a one-two.
The second win of the day in the men's fleet went to Italy's Giacomo Ferrari and Giulio Calabro, but they received a discretionary penalty as their boat did not weigh within the specifications laid out in the class rules.
They therefore received a 40 per cent penalty to their day’s scores and are ninth overall.
Spain's Barbara Cornudella and Sara López sailed consistently in the women’s fleet, picking up a third and a second to establish a lead on five points.
Compatriots Silvia Mas and Patricia Cantero are second and level on seven points with Britain’s Hannah Mills, the Rio 2016 Olympic gold medallist, and Eilidh McIntyre.
Pre-regatta favourites Afrodite Zegers and Anneloes van Veen of The Netherlands also have the same total.
Britain's Henry Wetherell and Ed Wright have the early advantage in the Finn on eight points, but the pack of racers behind them are closely bunched together with just nine points separating the top eight.
Wetherell and Spain’s Alex Muscat took the day's race wins.
France’s Jean Baptiste Bernaz and the United States’ Charlie Buckingham share the laser lead.
Both racers were consistent on the opening day and are level on five points.
Bernaz recorded a race win and a fourth, while Buckingham picked up a three-two scorecard.
Despite starting her day with a fifth-place finish in the laser radial, 2016 youth world champion Dolores Moreira of Uruguay moved to the top of the leaderboard with a bullet in the last race of the day.
Moreira is three points clear of Greece’s Vasileia Karachaliou, gold medallist at the 2017 World Cup Series event in American city Miami in January, on six.
The opening race win went the way of Belgium’s Evi van Acker, who is seventh overall.
Racing is due to resume tomorrow.