Wearing handcuffs but holding red roses, the 21 appeared in Alexandria courts in white prison garb in a case that has sparked an outcry.
Many bore the word "Freedom" written in Arabic and English on the palms of their hands, and smiled from the metal-caged dock.
The women and girls were convicted last month of taking part in a violent protest demanding Islamist president Mohamed Morsi's reinstatement following his overthrow by the army in July.
Their harsh sentences had shocked even supporters of the military-installed government.
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Lawyer Ahmed al-Hamrawy told the court there was no evidence to convict his clients and asked the judges to release them.
"Even in Mubarak's era there were morals. Egypt's women and girls were a red line and they weren't placed on trial," he said, referring to ousted dictator Hosni Mubarak, Morsi's predecessor.
"This is an oppressive sentence," one defendant, Salma, told AFP during a court recess.
"I have the right to express my opinion -- this is a constitutional right, and we are currently political prisoners," said another defendant, Aya Adel.
The prosecutor general's office charged that the women fought with knives and threw rocks during clashes that erupted during the protest in Egypt's second city.
Six men said to be Muslim Brotherhood leaders were tried in absentia in the same case and sentenced to 15 years.
They were found guilty of inciting the women to cut key roads in the city during the clashes.
During the recess, about 100 friends and relatives of the defendants stood outside the courtroom chanting "Down with military rule."
Hamrawy told AFP he expected the misdemeanour courts to either acquit them or release them on bail ahead of a final ruling.
The jail terms, coming in the same week as a restrictive new protest law, re-energised Islamist opposition to the interim government and drew criticism even from its secular supporters.
Hamdeen Sabbahi, a former presidential candidate and a leading dissident under Morsi, called on the interim president to pardon the girls and repeal the new law governing protests.