"We're announcing the expansion of offshore oil and gas exploration but in ways that balance the need to harness domestic energy resources and the need to protect America's natural resources."
Obama said his decision is part of a broader strategy that also includes expanding the production of nuclear power and other clean energy sources.
But he warned that expanding drilling is not the solution to the country's energy challenges.
"Drilling alone can't come close to meeting our long-term energy needs, and for the sake of our planet and our energy independence, we need to begin the transition to cleaner fuels now."
Seeking bipartisan support
White House officials have pitched the changes as ways to reduce US reliance on foreign oil and create jobs.
Obama also indicated that his decision was based in part on winning Republican approval for a climate change bill that has stalled in congress.
Obama, a Democrat, needs bipartisan support to pass the bill that would set limits on US greenhouse gas emissions.
"I know that we can come together to pass comprehensive energy and climate legislation that's going to foster new energy -- new industries, create millions of new jobs, protect our planet, and help us become more energy independent," he said.
Some senior congressional Republicans called the announcement a step forward, but said Obama did not go far enough.
"Today's announcement is a step in the right direction, but a small one that leaves enormous amounts of American energy off limits," Mitch McConnell, the Senate Republican leader, said.
For more than 20 years, drilling was banned in most offshore areas of the US outside the Gulf of Mexico because of concerns that spills could harm the environment.
Obama's plan offers few concessions to environmentalists, who have been strident in their opposition to more oil platforms off the nation's shores.
Environmental groups and some legislators continue to raise concerns about the impact increased drilling would have on coastal areas.
Tyson Slocum, the director of the Public Citizen's Energy Programme, which advocates for affordable, clean and sustainable energy, said the plan will not contribute to a climate change deal.
"It's bad strategy from Obama's strand point to give such a significant environmental concession, without knowing exactly what he's getting in return," he told Al Jazeera.
"In terms of addressing national energy security or lowering gasoline prices, the department of energy ... found that opening these areas to expanded off-shore drilling would only reduce gasoline prices in the US by an average of three cents a gallon.
"The United States is not Saudi Arabia. We do not sit on a mountain of oil reserves. This expansion is going to come at potentially great costs to sensitive ecosystems on the coasts."
Obama announced other energy proposals on Wednesday that were more likely to find praise from environmental groups, including plans to cut his government's direct dependence on petrol-only vehicles.
"In order to save energy and taxpayer dollars, my administration is doubling the number of hybrid vehicles in the federal fleet, even as we seek to reduce the number of cars and trucks used by our government overall," he said.
"We’re going to lead by example and practice what we preach: cutting waste, saving energy, and reducing our reliance on foreign oil."
The administration has been weighing the pros and cons of offshore drilling since it took office and put a hold on a Bush-era proposal which called for drilling along the East Coast and off the coast of California.