The city has filled only about half of the newly created pre-K seats it is funding, with one month to go until the program's January start.
As of Monday, 1,150 families had started the enrollment process for 2,000 available spots. Enrollment opened Oct. 20.
"We know from the district's pre-K and kindergarten registration that a lot of families wait until the last minute," said Deana Gamble, spokeswoman for the city's Office of Education.
"So we're not overly concerned at this point, but we're still actively reaching out to families to encourage them to sign up."
With the weeks that remain, officials are ramping up outreach efforts and seeking volunteers to canvas neighborhoods to spread word about the program, which they originally predicted would have an overflow waiting list.
There are plenty of young children in need of pre-K in Philadelphia. The city's Commission on Universal Pre-K found that of the city's 42,514 3- and 4-year-olds, only one in three is enrolled in high-quality pre-K.
There is no income cap for enrollment in the city's program, though most of the centers contracted are in low-income areas.
The city's pre-K program starts with the 2,000 seats in January and gradually increases to 6,500 seats over five years - as long as a sweetened-beverage tax created to fund it withstands a legal challenge.
The city has encouraged parents to sign up despite the pending lawsuit because the term for spring 2017 will be funded even if the tax is struck down.
The city will pay $10.2 million to pre-K providers at sites scattered throughout the city in this first round. Contracts were finalized last week.
Gamble said that despite the number of seats remaining, interest is high. The city's call center receives 100 calls a day, she said.
The city has advertised how to sign up in newspapers and on social media, subways, and the radio.
City Council members and state representatives were looped in to help in the final stretch, Gamble said.
On Monday, the city's Office of Civic Engagement and Volunteer Services released a list of volunteer opportunities and specifically highlighted canvassing neighborhoods to spread word about pre-K.
"Some families may be hesitant to switch their children halfway through the year, and we really need folks helping to educate potential families on the value of quality pre-K," Gamble said.
Families interested in enrolling their children can call 1-844-PHL-PREK. Eligible children must have turned 3 by Sept. 1, 2016, and families must live in Philadelphia.