The Syrian Democratic Forces (SDF), an alliance of local militias supported by a US-led coalition, had given the 210 women a 15-day course in armed combat.
Trainers taught the women weapons handling, tactics and first aid.
“The goal... is to stand up against Daesh, to stand up to them and tell them that the woman is strong,” said new recruit Layla Hussein, using the Arabic acronym for Isis.
Jihan Sheikh Ahmed, the SDF spokeswoman for the Raqqa campaign, said the women would be mainly deployed to the battlefront against Isis in Raqqa.
Another course will start in two months, she added, and there will be more as the demand continues.
Hussein said her training had included ideology sessions.
The SDF is dominated by the Kurdish YPG militia, which follows the leftist ideology of Abdullah Ocalan, the leader of the Kurdistan Workers Party (PKK) that has fought a three-decade insurgency in Turkey.
The spokesman for the US-led coalition initially said all the women who had been trained in that group were Arab but later said it was checking that information. A witness to the ceremony said some of the new fighters were Kurdish.
“Since the beginning of the revolution and continuing on until now, the main casualties of war have been women,” said Sarya Mahmoud, a trainer and commander in the YPJ, the all-female brigade in the YPG.
The female fighters give hope to women in the towns they liberate, Mahmoud said, “because were going to free them and give them the volition they lost years ago, not just from Daesh, but from the male mentality and the government mentality.”
The new SDF fighters came from different parts of northern Syria, including Deir al-Zor, Raqqa, and Aleppo, and will be deployed directly to Raqqa, where the SDF launched a campaign to seize the city from Isis forces in early June.
Isis has lost large expanses of territory in Syria over the last year to separate campaigns waged by the SDF, the Russian-backed Syrian military, and Turkey-backed Syrian rebels.