President Biden on Tuesday announced his long-awaited first slate of ambassadors, including his nominees for key posts in Mexico and Israel, as he made his first trip abroad since taking office.

As was expected, Mr. Biden announced he was nominating Ken Salazar, a former senator of Colorado who served as secretary of the Interior Department in the Obama administration, as ambassador to Mexico, and Thomas R. Nides, a vice chairman at Morgan Stanley who served as a deputy secretary of state under President Barack Obama, as ambassador to Israel.

The official announcements of the long-rumored nominations came as Mr. Biden traveled to Europe with the goal of demonstrating to global leaders that “America is back at the table.” Mr. Nides’s nomination also came just days after a new government took power in Israel, opening up the possibility of a less contentious relationship with the Biden administration.

Middle East experts praised the selection of Mr. Nides. “He has the relationships to quickly get access to the very top of the administration at the White House and the State Department,” said Ilan Goldenberg, a former Obama administration official who is now director of the Middle East Security program at the Center for a New American Security.

Mr. Biden on Tuesday also announced that Chesley B. Sullenberger III, the pilot who executed a water landing off Midtown Manhattan after a dual engine failure brought his plane plummeting toward earth, as his nominee for ambassador to the International Civil Aviation Organization.

Other nominees announced Tuesday included Julianne Smith, currently an adviser to Secretary of State Antony J. Blinken, to serve as ambassador to NATO.

Tuesday’s announcement was expected to be the first batch of a multiweek rollout of nominees. Some of Mr. Biden’s selections for the most significant posts abroad — including R. Nicholas Burns, a veteran Foreign Service officer and a former ambassador to NATO, to serve as ambassador to China, and Mayor Eric Garcetti of Los Angeles to serve as ambassador to India — were not announced on Tuesday, even though several people familiar with the process said their nominations had been finalized internally.

The White House press secretary, Jen Psaki, has noted that the process takes a long time in part because “countries have to agree to these selections, and so sometimes that’s part of the timeline.” Some of Mr. Biden’s nominees who were not officially announced Tuesday, but who have been selected, are also still completing time-consuming background checks and financial reviews as part of the rigorous vetting process, White House officials said.

Some of the announcements have been delayed as the White House has sought to roll out a diverse slate of appointees. In addition to racial and gender diversity, Mr. Biden also wanted to signal to career Foreign Service officials that they are valued by whittling down the number of posts given to campaign donors.

That was apparent among the nine names Mr. Biden announced on Tuesday, ahead of his high-stakes meeting with President Vladimir V. Putin of Russia.

Mr. Biden announced the nominations of four career Foreign Service officials to serve in ambassador posts. They included Troy Fitrell to serve as ambassador to Guinea; Sharon L. Cromer to serve as ambassador to Gambia; Julie Chung to serve as ambassador to Sri Lanka; and Marc Ostfield to serve as ambassador to Paraguay.

Mr. Biden also nominated Dr. Cynthia Ann Telles, a clinical professor in the University of California, Los Angeles psychiatry department, to serve as ambassador to Costa Rica. Ms. Telles was also a founding board member of Americas United Bank, the first Hispanic commercial bank to be chartered in California in over 30 years, White House officials said.