"Details to follow", he tweeted out Wednesday night.
Sources familiar with campaign operations cautioned that while Pence and former House of Representatives Speaker Newt Gingrich were finalists, Trump could always have a last-minute change of heart and choose someone else from his short list.
Two finalists in Trump's search for a running mate made the list as well: New Jersey Gov. Chris Christie and Newt Gingrich.
In addition, US Senator Jeff Sessions, 69, of Alabama, a fourth potential candidate for the VP spot and a close adviser to Mr Trump, was seen going into the Conrad Hotel in Indianapolis, where Trump was recently located.
In Pence, Trump could find an effective fundraiser with close relationships to wealthy donors who have so far declined to back the businessman's insurgent campaign, and an enthusiastic campaigner who can bridge the divide with a distrustful Washington establishment still smarting over their nominee's say-anything style.
"It's clearly serious. He's clearly in the final group", the source said.
When asked whether he would be surprised if Indiana Gov. Mike Pence is chosen instead, Gingrich wrote, "Would not be surprised".
The question now, as the show sprints to its denouement Friday when Trump will announce the victor, is what exactly the presumptive nominee really wants in his vice president? Traditionally, the vice presidential choice is used to build enthusiasm among party loyalists.
"I'm honored to be considered and humbled to be considered", Pence told reporters Wednesday.
Republican Sens. Marco Rubio, Bob Corker, Rob Portman, and Joni Ernst have all said they weren't interested in the job. Gingrich also met with Trump during the day, while Christie talked with him on the phone. Trump's children Donald Trump Jr., Eric Trump, Ivanka Trump and her husband, Jared Kushner, and campaign chair Paul Manafort joined Trump Sr.at Pence's home in IN this morning.
Pence has led IN since 2013 and is locked IN a tight race for re-election.
Trump said a breakfast Wednesday with Pence and the Trump family "went really well". The Indianapolis Star has reported Pence "swore off harsh political tactics". He was forced to abandon plans a year ago to create a state-run, taxpayer-funded news service in his state after coming under criticism for the move.
Pence's departure for national politics sets up a scramble among Indiana Republicans to determine who will replace Pence to run against Democratic challenger John Gregg in the November gubernatorial election.
Lewandowski helped Trump upset 16 primary rivals, a stunning feat for the political novice and a campaign manager with little presidential campaign experience.
All the while, Trump was surrounded by the people he trusts most -- his grown children, Eric, Donald Jr. and Ivanka.
One of his main platforms is education reform, and he is also known for reaching across the aisle to work on legislation.
"Well let me say first and foremost, I stand by this law", he said.
But at age 73, Gingrich could have trouble appealing to younger voters. The AP reported last month that almost every Trump employee - both in the campaign and his businesses - must sign legally binding nondisclosure agreements prohibiting them from releasing any confidential or disparaging information about the real estate mogul, his family or his companies.