The pair now face weeks of grappling with the punishing effects of prolonged weightlessness.
Senior Nasa administrator Joel Montalbano described the landing as "beautiful" and said their 150 experiments and 900 hours of research will inform future moon missions.
Nasa manager Steve Stich said:
"The crew is doing great. Eventually they will make their way back to Houston." He added the pair will get some "well-deserved time off" with their families after debriefing.
Doctors warned they would be unable to walk unassisted when they touched down, having spent far longer than planned in the micro-gravity environment of space.
The astronauts were originally only scheduled to be in space for an eight-day mission when they blasted off from Kennedy Space Centre in Florida on June 5.
But their stay was dramatically extended due to a catalogue of technical failures with their spacecraft, Boeing's troubled Starliner.
Dr Vinay Gupta, a respiratory specialist and former US Air Force medical officer, said: "Living in low gravity leads to muscle atrophy and bone density loss, meaning they will struggle to stand or walk on their own initially.
"They will need up to six weeks of rehabilitation to regain their strength." Wilmore and Williams began their recovery programme the moment they landed.
The first phase will focus on walking, flexibility and muscle...