The team left Pyongyang for Beijing after spending four days in North Korea.
Richardson earlier called the visit a "private humanitarian mission," although the U.S. State Department had said its timing wasn't helpful in view of the North's long-range rocket launch last month in violation of U.N. Security Council resolutions.
"It is a productive and successful trip," Richardson told China's official Xinhua News Agency. He was quoted as saying he and other members of the delegation "had a good opportunity with the Korean people and talked about the expanding of Internet, cellphones and more communication."
Schmidt declined to answer questions during the visit, Xinhua said.
While in North Korea, the Americans met with North Korea Foreign Ministry officials, visited the electronic library of Kim Il Sung University and the Korean Computer Center.
Xinhua said when he arrived in North Korea Monday, Richardson said he and his delegation were interested in North Korea's economic and political situation and believed in the importance of dialogue.
Richardson, who has traveled to North Korea several times in the past two decades, was expected to try to discuss the case of Korean-American Kenneth Bae, who has been detained for more than two months for allegedly "hostile acts against the republic," South Korea's Yonhap News Agency had reported.
North Korea's official Korean Central News Agency had reported on Dec. 21 that Bae had made an admission and that he would face legal action.
However, Xinhua said Richardson didn't say Thursday whether he met Bae.
CNN reported many North Korea watchers remained puzzled by the presence of Google's executive chairman in the delegation. Last week, a Google spokesman said in a statement the company doesn't comment on "personal travel" by its executives.
Prior to the visit by the U.S. delegation, State Department spokeswoman Victoria Nuland said, "Frankly, we don't think the timing of this is particularly helpful but they are private citizens and they are making their own decisions."
North Korea has come under intense international criticism for its Dec. 12 rocket firing as it was seen as a test of its ballistic missile technology. Pyongyang is under tough sanctions for conducting nuclear tests in 2006 and 2009.