Before making his presidential bid announcement, Bloomberg has plans to spend an estimated $15 million to $20 million on the effort.
The plan was confirmed by Bloomberg's team on Wednesday.
It comes less than a week after the former New York City mayor unveiled a $100 million online advertising campaign attacking Trump in four general election swing states as well.
The new effort has specific targets, 500,000 voters from traditionally underrepresented groups that typically lean Democratic, including African Americans, Latinos, Asians, young voters and those living in some rural communities.
The drive will begin early next year in Arizona, Michigan, North Carolina, Texas and Wisconsin, but could expand to more states.
The move marks another significant show of financial force demonstrating Bloomberg's ability to run what senior adviser Howard Wolfson described as parallel campaigns over the coming year.
Bloomberg has already filed paperwork to qualify for presidential primary ballots in three states. The 77-year-old former Republican and independent, who formally registered as a Democrat just last year, is expected to make a formal announcement about his 2020 intentions in the coming days.
The new voter registration drive targets voters across five states that Trump won in 2016 largely by narrow margins.
The Associated Press contributed to this article.