Taiwanese men are required to do mandatory military service and reservist training, but women can also volunteer to serve in the armed forces.
On Tuesday the former women soldiers pulled gas masks over the heads, crawled across a playground, patrolled streets by a temple and performed other mock defence exercises.
“Poisonous gas dissipated, clear to take off masks!” one of their officers yelled before they quickly removed their gear.
Reservist Tang Mi – who is a realtor – said that “with no country, there’s no home”.
“That’s why I’m here – because what concerns the country is everyone’s business,” the 26-year-old said.
Military analysts have urged Taiwan to do more to boost its reservists and prepare the civilian population for a potential invasion, including by allowing more women to train.
Some lawmakers have proposed including women in some form of mandatory service.
Tensions between Taipei and Beijing soared last year after China staged massive military exercises around the island in response to then-US House speaker Nancy Pelosi’s visit to Taiwan.
Last month, Beijing conducted war games simulating a blockade of the island in protest against a meeting between Taiwanese President Tsai Ing-wen and Pelosi’s successor Kevin McCarthy in California.