"The criminals take refuge in these sanctuary cities and it's very risky for our police and enforcement folks, " he said.
The visit - Trump's first to the state as president - coincided with an escalating battle between his administration and the liberal state, which Democrat Hillary Clinton easily carried in the 2016 presidential election.
Gov. Jerry Brown, a vocal Trump critic, tried to find common ground with the president.
Air Force One landed at a marine corps air station in Miramar, outside San Diego, the Guardian reported.
Last week, Mr Trump's Justice Department filed a lawsuit accusing California of violating the US Constitution and putting federal agents in danger by approving laws protecting illegal immigrants.
If Trump could rise above politics and let go of grudges, he just might see how important California is to the success of his presidency and to America's prosperity.
"People are so narrow-minded, " the Riverside firefighter said as the crowd chanted.
Last week, the Trump administration sued California over its sanctuary laws and Brown responded that the feds had declared war on the state.
Each prototype Trump viewed Tuesday cost $486,000, DHS said, and the winning bidders on the project are to be selected around June 1.
Trump's criticism focused on tax policy, too, with the President mentioning owning property in California.
He renewed complaints that Los Angeles, San Francisco and other major cities are providing protection for illegal immigrants who have committed crimes.
The president called on Congress to include at least $12 billion for the wall in its upcoming budget and urged lawmakers to deny federal money to sanctuary jurisdictions like California that have become "the best friend of the criminal".
"Neither the United States, California, nor our local communities need this costly and divisive wall", according to a statement from the ACLU of San Diego and Imperial Counties. Rodney Scott, the Border Patrol's San Diego sector chief, helps the president hold the illustration.
California has been at the forefront of resistance to the Republican leader's anti-immigration agenda and at odds with his stance on a number of other issues, from gun control to marijuana and the environment.
Ahead of his arrival, the president tweeted that "thousands of risky, violent criminal aliens are released" as a result of California's immigration sanctuary policies.
"You have to have see-through", Trump told reporters. "THIS MUST STOP!" he wrote.
Trump has long said he wanted to visit the models himself so he can pick a victor, though the Department of Homeland Security says elements of each design are expected to be used. But, he said, "I have to do it". His administration has requested US$18 billion that would build about 480 kilometres (300 miles) of new barrier where none exist and would replace older sections of fencing.
Jeff Schwilk, founder of San Diegans for Secure Borders, said the City Council's resolution does not reflect the views of many residents, who feel the border is not secure.
"It's not good", said Mauricio Villegas, 37, glancing toward the fence and prototype walls as he passed through on his way to a job at a veterinary office.
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