As anticipation mounts that Mr Biden will not contest the 2024 election, sources close to Ms Harris say she "wants to be seen more".
As other senior Democrats look to raise their profiles, Ms Harris appears to be positioning herself for a White House run.
The first female, black and south Asian VP currently suffers from similarly poor approval ratings as Mr Biden – and has at times been less popular than the 79-year-old veteran.
But the former California senator, 57, has been travelling around the US significantly more, making eight domestic visits in July alone.
US Vice President Kamala Harris
HANNAH BEIER
US President Joe Biden on a call with business leaders this week
JONATHAN ERNST
That figure is twice the number of any other month in office – her average per month this year is just three domestic trips.
Within the Democratic party, Ms Harris' movements appear to have sparked potential rivals into gear.
Gavin Newsom of California, for example, has been taunting Republican governors in Florida and Texas.
Her main point to champion is the Supreme Court's Roe vs Wade ruling – and she has visited crucial swing states such as Florida, Pennsylvania and North Carolina this month.
Ms Harris told The 19th: "I plan on travelling around our country, talking to folks, listening to folks.
"Women and men are upset, angry and terrified about the rights that are being taken."
She is aiming to frame an “unfinished business, not broken promises” campaign focused on fulfilling the US government's failure on pledges such as codifying abortion, passing climate change protections and forgiving some student loan debts.
Ms Harris has held private meetings with three important backers who helped organise her successful California campaigns to be district attorney and attorney-general and to reach the Senate, CNBC reported.
It comes amid calls for Mr Biden to announce he will not run again, with the nickname "one-term Joe" emerging in the US media.
A New York Times-Siena College poll this month found that 64 percent of Democrats said they would prefer a different candidate in 2024.
Mr Biden has said publicly and privately that he intends to seek a second term.
Ms Harris last month said: “The president intends to run and if he does, I will be his ticket-mate. We will run together.”