“We’re pretty excited,” Ms. Wei said, noting that they had woken up early for the occasion. “But we’re also pretty tired,” she said, with a laugh.

“We’re very happy,” Ms. Tseng said.

Alongside Ms. Lu, Chi Chia-wei, the white-haired and bespectacled godfather of Taiwan’s gay rights movement, beamed as he took in the scene. Dressed in a bright orange jacket and wearing a rainbow headband and tie, he knew more than anyone how far the movement had come. In 1986, when now-democratic Taiwan was under brutal martial law, Mr. Chi was imprisoned for coming out as gay. Thirty-three years later, his battle is still not over.

“Progress is good,” he said. “More progress is even better.”

Mr. Chi said that Taiwan’s separate-but-equal law for same-sex couples was a step in the right direction, but that more work remained to be done. Instead of having a separate law for gay couples, he said, Taiwan’s civil code should be amended to simply include all couples. The issues of transnational couples and full adoption rights also need the be addressed, he said.

Nevertheless, Friday’s marriage registrations capped three years of hope and disappointment for Taiwan’s LGBT community. The struggle began in earnest in 2016 with the election of president Tsai Ing-wen, the first Taiwanese president to voice approval for same-sex marriage.

As a candidate in 2015, Ms. Tsai expressed support for marriage equality, and her election in 2016 generated excitement among same-sex marriage supporters.

But months after Ms. Tsai assumed the presidency, it appeared that same-sex marriage was not a policy priority. In the 2017 legislative session, Taiwanese conservatives mobilized to oppose any attempt at legalization, causing many lawmakers with Ms. Tsai’s ruling Democratic Progressive Party to withdraw support, leaving the bills in limbo.