Nada Arakji, the first ever Qatari woman to compete in the Olympics when she swam in the 50m freestyle four years ago, will this time compete in the 100m butterfly.
Also heading to Rio is runner Dalal Al-Harthi who will race in the women's 400m.
In total, Qatar is sending a team of 38 athletes, said officials although there was no official comment.
The drop in female athletes comes despite Qatari Olympic selectors claiming earlier this year that they hoped the number of women competitors would increase.
This is the eighth Olympics at which Qatar has competed and there is expectation that the country can land its first ever gold medal.
Possibly the biggest hope is high jumper Mutaz Barshim, who won bronze in London and earlier this year claimed his fourth Asian Indoor Athletics Championships at the age of just 24.
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Another gold medal prospect is the handball team, which took silver at the world championships last year, losing out to France in the final.
The team though has attracted criticism in the past for the number of non-Qatari born players in the side.
Also going to Rio is Nasser al-Attiyah, a former world rally champion who won bronze at the men's skeet, a shooting event, in 2012.
In total, Qatar has won four Olympic bronze medals.
The energy-rich emirate, which will host the 2022 football World Cup, has poured huge resources into training young athletes to get them to world-class standard and Rio is a big test for its training programme.
Earlier this year, the head of the country's Aspire Academy, the Doha site where young Qatari athletes are trained, said it could double the number of Olympic medals won by the tiny Gulf country at Rio.
Qatar has also made it clear it is likely to bid to host a Summer Olympics, possibly as early as the 2028 games.