The agency issued the announcement on Tuesday after reported an increase in COVID-19 infections and hospitalizations.
This advice notably includes travelers who are current with their vaccines and boosters.
Previously, the recommendation to test before domestic travel applied to those who weren't up-to-date with their COVID vaccines.
There's also testing guidance for after your trip is over, especially if you've been spending time in areas crowded with people.
The CDC recommends taking a COVID test after domestic travel "if your trip involved situations with greater risk of exposure such as being in crowded places while not wearing a well-fitting mask or respirator."
Finally, the agency reminds travelers to be aware of local rules and conditions wherever they're going within the United States. Don't assume what holds true in your town or state is the same somewhere else.
"I agree with that," said Rhea Shannon of North Hollywood. "I've been doing that since the pandemic started. I had to travel even during while we're shut down, and I didn't want to infect anyone that I was going to see, and I didn't want, you know, to not know where I got it from. So I always do that."
Bernice Mentzer, who was traveling to Washington on Tuesday, told ABC7 she's on board with the change as well.
"I really like that idea," she said. "I used to be a school teacher so I work with the public, I work with students. I also have a senior mother and senior in-laws so I'm always healthy, I always wear my mask."
These domestic updates are separate from CDC guidance for those traveling to the U.S., including U.S. territories, from abroad.
Those travelers must have a negative coronavirus test within a day of travel or submit proof that they've recovered from COVID in the previous 90 days. Children younger than 2 do not need to test.
The CDC also recommends getting tested three to five days after international travel to the United States.
Additionally, foreign citizens must be vaccinated for COVID to enter the United States. No such requirement exists for U.S. citizens, U.S. nationals, and lawful permanent residents traveling domestically or internationally.
Still, the agency recommends that people be up-to-date with vaccines before any air travel.
CNN contributed to this report.