Their observance, though, comes as Israel is at war, putting a focus on security for many local synagogues.
A guard stood watch over the entrance of B'nai Abraham Chabad synagogue in Center City as congregants attended service.
"You don't want to have to put a security guard outside because it kind of broadcasts the message that you need it. But a the same time, you want the best safety for your children," said Isaac Steinberg when asked about the security at his synagogue.
READ MORE: Security top of mind for local Jewish community
Security top of mind for local Jewish community
Temple Beth Zion-Beth Israel in Rittenhouse Square also had a security guard at the entrance with a marked police unit out front.
Rosh Hashanah is happening this year amid Israel's war with Hamas and Hezbollah. It also comes near the first anniversary of the October 7 terrorist attacks. The current world situation puts even more of an emphasis on synagogue security for police in Lower Merion, which has a large Jewish population.
"You'll definitely see marked police vehicles. You'll see uniformed police officers," said Det. Sgt. Michael Keenan of the Lower Merion Police Department. "We make sure we are very visible. We make sure we're attentive to our community's needs and our friends and neighbors and we are visible to our folks in the synagogues."
Philadelphia police are doing the same. The department sent a statement to Action News detailing its focus on security.
"Out of an abundance of caution, we have taken proactive measures, including increased patrols around local Jewish and Islamic places of worship and community centers, to ensure the safety of all community members," read the statement.
"We want people to feel safe and we want them to feel protected to worship in their own way," said Keenan.
Even after Iran launched a missile attack Tuesday night, some of the faithful like say they're not afraid.
"It's important to be together and to stand strongly with Israel. In fact, I'll go next month to Israel for a week," said Ed Baumstein as he left Rosh Hashanah service.
Through the turbulence, congregants like Spencer Brennen find comfort in their faith.
"Any time you can be a part of a tradition that is far larger and greater than yourself, it's a tremendous source of comfort to know that you stand on generations," Brennen said.
Rosh Hashanah continues through sundown Friday with many synagogues planning more services that will undoubtedly include more security.