The rollout will be a "multi-pronged approach," the the Centers for Disease Control and Prevention advisory panel said, including vaccination sites already in operation, major retail pharmacies, mobile health clinics, schools and family doctors.
The name of the game will be meeting kids where they are, experts say, and as with adult vaccinations, that will vary state to state.
Appointments for those 12 and older were already opening up late Wednesday on CVS and Walgreens platforms. Both are set to begin giving the Pfizer vaccine to the newly eligible group Thursday, either with scheduled appointments online, through their apps or over the phone. They're also accepting walk-ins, but CVS said parental or legal guardian consent and accompaniment will still be required.
If local pediatricians aren't yet set up, Vaccines.gov, created by the Boston Children's Hospital, offers a starting point to search for the Pfizer vaccine, which has a formula and doses for ages 12 and older that is the same as adult shots. Currently, Moderna and Johnson & Johnson are only available for those 18 and older.
The Biden administration announced plans to ship Pfizer doses directly to pediatricians' offices, which they have stressed will be an important partner in this effort, encouraging governors to help enroll family practitioners and pediatricians "as quickly as possible."
Schools offer a central hub, but health experts are eyeing two critical points on the calendar: the close of the academic year for summer and the back-to-school buzz of August.
"There's an urgency right now to taking advantage of the unifying framework that the academic school year provides," Dr. Nirav Shah, director of Maine's CDC, said this week, anticipating the panel's vote. Maine is trying to get shots in kids' arms "before they fly to the wind over the summer."
But with the academic year coming to a close, fast outreach is critical, Dr. Anne Zink, Alaska's chief medical officer, said. Some of her state's 52 independent school boroughs and districts had already booked in-person vaccination clinics in their school for Thursday and Friday, anticipating the announcement.
Maine plans to have vaccinators go directly into schools, Shah said.
And later on this summer, the U.S. Department of Health and Human Services will launch "back to school" partnerships to support vaccinations as part of annual physicals and sports physicals.
The Biden administration, states, counties and school districts nationwide are looking for new and creative ways to reach younger adolescents that offer both comfort and a brisk rate of vaccinations.
The Children's Minnesota hospital system plans to begin vaccinating children ages 12 to 15 on Thursday by appointment only; in the coming weeks, they plan to provide shots in several local middle schools. Their main site has colored lights, and images of dolphins projected on the ceiling.
Finding "trusted messengers" to reach teens, including celebrities and influencers who have the ability to reach out to families, will be an aim of the Biden administration. They will also use so-called "micro influences" on the ground such as faith-based leaders, community organizations and school leaders.
"There's a lot of misinformation out there, and disinformation," Dr. Erica Pan, state epidemiologist at the California Department of Public Health, said Tuesday. "So really, [we're] trying to address those myths and questions so that people can get their questions answered."
Persuading this newly eligible age group will come with unique challenges: minors live under the jurisdiction of their parents or guardians, who typically must provide consent. And with hesitance still lingering among some kids and parents, getting both on board will be critical, experts say.
"You have in effect not one patient, but two patients -- the parents and kids," Shah told ABC News. "[The goal is] making the case that the vaccine is safe, and COVID remains a serious problem that can affect kids."
In Detroit, parents will need to accompany their kid to get the shot, Mayor Mike Duggan said Wednesday. Maine will not require a parent be on site, Shah said. They'll allow for verbal consent, like getting the parent on the phone to sign off.
"Adolescents have to be brought into the process," Shah said. "It's the consent of the parents, but the assent of the child."
Experts emphasize the importance of removing barriers to the vaccine for young adolescents, especially with concerns over shots' equity to more vulnerable communities.
"Twelve- to 15-year-olds, and under, are going to be at the mercy of whatever constraints their parents might have," Dr. Yvonne Maldonado, chief of Stanford University School of Medicine's Division of Pediatric Infectious Diseases, told ABC News.
"We need to make sure weekends and evenings are available for families who need to work during the day, that they're located in places that are close enough to families who may not have cars, or who may need to take public transportation."
In the coming weeks, Columbus, Ohio, public health nurses plan to drive a mobile vaccination unit around neighborhoods, "just like you would an ice cream truck," said Dr. Mysheika Roberts, the city health commissioner.
Many of Alaska's drive-thru evening sites are converting to Pfizer sites this weekend, Zink said.
"When mom is coming home from work or you know, dad's finishing a shift, they can just drive through," Zink said. "These kids live in families that are busy. And we want to make sure that is easy and convenient as possible."
ABC News' Anne Flaherty, Eric M. Strauss, Sony Salzman and Brian Hartman contributed to this report.