Bedouin tribesmen abducted the female American tourists and their Egyptian tour guide at gunpoint in broad daylight.
They were on their way from St. Catherine's Monastery to the Red Sea resort town of Sharm el-Sheikh.
The gunmen were demanding the release of several of their fellow tribesmen arrested this week on drug trafficking and robbery charges.
The hostages were released several hours later after negotiations with tribal leaders in the Sinai Peninsula.
U.S. State Department spokesman Mark Toner confirmed the release of the Americans and thanked the Egyptian authorities for their quick response to the kidnappings.
"We certainly appreciate the efforts of the Egyptian authorities in securing the releases," he said at a news briefing.
He said he could not name the Americans because of privacy considerations.
Also Friday, four gunmen stopped the car of two Italians working for a local food factory in the city of Suez. They took the car, more than 10,000 euros ($13,000) and laptops. The attackers, however, let the Italians go.
The abduction of the Americans was a new blow to Egypt's vital tourism industry, which has been heavily battered by the unrest following last year's uprising that ousted former President Hosni Mubarak.
Tourism Minister Mounir Abdel-Nour said last month that the number of tourists who came to Egypt in 2011 dropped to 9.8 million from 14.7 million the previous year. Revenues for the year clocked in at $8.8 billion compared to $12.5 billion in 2010.
The Associated Press contributed to this report.