The Prime Minister confirmed that European Union countries will be treated the same as those across the rest of the world when the new system is introduced after the Cabinet agreed the move last month.
Tourists and visitors making short trips to the UK from low-risk countries would be dealt with swiftly through electronic visa checks.
Mrs May, who remains committed to the goal of cutting net annual immigration below 100,000, said the long-awaited Tory plans would be fair for "ordinary working people".
She said: "Two years ago, the British public voted to leave the European Union and take back control of our borders.
"When we leave we will bring in a new immigration system that ends freedom of movement once and for all.
"For the first time in decades, it will be this country that controls and chooses who we want to come here.
"It will be a skills-based system where it is workers' skills that matter, not where they come from. It will be a system that looks across the globe and attracts the people with the skills we need.
"Crucially it will be fair to ordinary working people. For too long people have felt they have been ignored on immigration and that politicians have not taken their concerns seriously enough.
"The new skills-based system will make sure low-skilled immigration is brought down and set the UK on the path to reduce immigration to sustainable levels, as we promised. At the same time we are training up British people for the skilled jobs of the future."
Home Secretary Sajid Javid is preparing to set out the immigration blueprint in a speech to the Conservative Party conference.
He told Tory grassroots at a meeting on the fringes on Monday that he wanted an open system that allowed Britain to attract the best talent from across the globe.
It comes after the Migration Advisory Committee published a Government-commissioned report last month.
The committee said that if immigration is not part of the negotiations with the EU and the UK is deciding its future system in isolation there should be no preference given to citizens from the European Economic Area (EEA).
The bloc includes the present 28 EU countries, as well as Iceland, Norway and Lichtenstein.
Ministers will publish a white paper setting out details of how the new system will work in the coming weeks ahead of an Immigration Bill next year.
So-called fly-in, fly-out visitors on short trips from certain countries would be fast-tracked through e-gates.
Security and criminal records checks would be carried out ahead of landing under the proposals.
Successful applicants would be able to bring immediate family into the UK on condition of sponsorship by their future employers.
Mr Javid said EU free movement would end under the plans.
He told the Daily Mail: "If you want to come to our country and contribute, great. But, in exchange, we expect you to live by our British values and respect our values."